How about a hinge on one of the short sides, with the mirror on the inside for protection. The magnesium bar and flint can extend down the full thickness. The plastic fresnel lens is more durable, so it can go on the bottom without protection(a folding plastic cover on the same hinge, to protect to bottom, would be nice, but would probably add too much thickness and complexity.)
The space in between the mirror and lense could hold a tindercard, and some ultra-thin plastic sheets printed with survival instrutions in a tiny font, to be read with the fresnel lense. Experienced people would have the option of replacing the instructions with an extra tindercard, photo, etc.

A thin, partially serrated knive could fit on the top of the card, above the back of the mirror, behind the magnesium bar. It would run the full length of the card, be partially serrated, and be a one piece unit with a small knurled metal handle. The end of the handle could be designed to lock into the side of the card opposite the hinge, to provide a more substantial handle(This would be a great feature but may not be possible, since most of that side is taken up by the flashlight and space for the knife handle. There may be room in between, although locking the knife to the middle would be slightly less functional than to the bottom). The knife would either slide into a recess in the top of the card, or lock onto the top in such a way that the edge is protected.

The flashlight would be opposite and parallel to the knife. Since the L.E.D. itself is too thick, the bottom half below the electrodes could wrap around the edge of the mirror, flush with the bottom of the mirror and the top of the card. 2 CR2016 batteries would be end-to-end, not stacked like most coin cell flashlights, so the flashlight unit would be fairly long. Stacked batteries would be way too thick, leaving no room for a casing and switch(think about a photon, that's thicker than the entire card should be). The flashlight would be removable, locking to the top of the card, and have a small lanyard hole.

The compass would be behind the flashlight, non-removable, about the diameter and thickness of a CR2016 battery, with luminous markings(not that it makes much of a difference, since the flashlight is needed to charge the luminous crystals).
Between the knife and light, opposite the hinge, would be a lanyard hole that goes through both halves. This hole could serve double duty as a snap.

A small aiming hole for the mirror would be directly in the middle of the card. The narrow rectangle between the
knife, light, lanyard hole and aiming hole, could be used to hold a small narrow whistle which snaps into the card. This would be thin and not very loud, but much better than nothing.

This would leave one small area of the card for storage or other usage, roughly a square bordered by the compass, knife, flint and hinge. If used for storage, a plastic or metal lid could snap on to cover the area, leaving just enough room for some thread, a few hooks or small safety pins, etc. The space would be so limited that I can't think of anything worth putting in there, I'm sure it could be better utilized for something else. A small "V" style sharpener with tiny tungsten rods would occupy roughly 1/5 of this space if designed cleverly, and would neccesitate the removal of about 1/2 a centimeter of the flint rod or magnesium bar. For most people this would be far more practical than a diamond sharpeneing surface, especially considering the market for this type of device. One possible use for the remaining space is an analog or digital clock, useful for measuring distance. A
tiny version of the flosscard may be the best thing for the remaining space. It would be far more useful if it contained a high strenth fiber such as kevlar or specra instead of floss.

The case itself would have to be made of a thin, strong, hight density metal, such as steel or possible anodized aluminum. Any type of plastic or lexan would be far too thick or increadibly weak. Carbon fiber might be an option, I'm not that familiar with it's properties. Titanium is out of the question, most people have the false idea that it is stronger than steel, it is actually much weaker by volume. However a titanium oxide coating(or other titanium compound, I'm not that familiar with metalurgy), might be a good option if it allows the use of high carbon steel instead of stainless, since that may allow it to be thinner. All sides of the card must be smooth and flush, to make it easy to insert and remove from a wallet, to prevent damage to the card and the wallet, and to prevent items from being accidentally removed.

If coloring the card is practical, bright orange, or possibly yellow is the best choice. For people who like glow-in-the-dark, keep in mind this card will rarely see the light of day, and even if charged with light, will not retain any significant brightness for long. If nightime visibility is that important, there is probably room for a small traser(tritium vial coated with phosphorous, very bright in complete darkness and needs no light charge)

All of the card tools I've seen on the market are too thick to be practical to carry in a wallet, and even this one would be too thick for some people. Whatever the size, don't dare describe it as credit-card sized, whoever is responsible for describing those other products as such deserved to be smacked repeatedly. In order to make this work, it would require top of the line materials, quality precision machining, and would not be cheap, costing at least $30.

One more thing. As far as including any sort of medical items or water purification, there's nothing you could possibly fit in a card that would be useful, except possibly a tiny container of superglue, a wound closure strip without the sterile packageing, or maybe a suture, (which for most of us would do more harm than good). Bandaids have there place in larger first aid kits, but in terms of life and death survival, are about as useful as pocket lint, (possibly less, depending on how much lint you have and how dry it is). You could not fit a full course of treatment of even the best antibiotic. If you had a card with meds and nothing else, and it was on the thick
side, you might be able to fit some useful meds such as painkillers, loperamide or other diareah meds, and antihistamines. You still couldn't fit antibiotics, and any other meds that you could fit would simply be luxuries. I guarantee you that noone is going to carry both a med card and a survival card in there wallet, and choosing a med card instead of a survival card would be a very poor choice.

I personally keep a few alcohol and iodine pads in my wallet, because they take up less space than a credit card and can be used as tinder and for water purification in addition to medical use. If you really want to keep a valuable medical item in your wallet, one of the smaller packets of quick-clot might fit. It's not small, but is probably the only first aid item that can fit in your wallet and save your life.

Sorry for the really, really long post, I went a bit overboard.