I've done the 35mm film canister thing. I forget the contents now. The smallest kit than I can currently find is a tin about 2 inches square and half an inch thick. Contents:

• Mirror card (cut to size).
• Ferro rod (cut to size).
• Hacksaw blade striker (cut to size).
• 3 Tinder-quik tabs.
• Water purifier tablets.
• Button compass.
• Photo Freedom torch.
• Tweezers (from a small SAK).
• Pen (from a small SAK).
• Some waterproof writing paper.
• 3 safety pins.
• Scalpel blade (stronger and easier to use than a razor).
• Cord (a yard or so).
• Cotton wool (to prevent rattling).

It's years old. Now that I look at it again I think it's pretty cute, with a lot of bases covered in a small space. I am not into fishing or snaring; food isn't a priority for this kit. Nor am I a fan of matches. The torch and compass work; I guess the water tablets are expired.

I think the mirror card came from Minsets Online. It comes as a big sheet. I have cut it to just smaller than the tin, so it fits under tin's inner lip, compresses everything beneath it and takes pressure off the lid. It won't be perfectly flat, and a glass mirror would be better, but it's light and not fragile and probably more reflective than trying to polish the tin itself.

What I actually EDC now is less a kit and more odds and ends in various places about my body. My keychain has more cordage, a better ferro rod and striker, a whistle, and I have better torches and knives in other pockets.