I've been working and reworking my PSK for two winters now. First, I used a 4015 military surplus canteen/utility pouch with a Vietnam era metal canteen cup as a container for my kit. When I field tested it, I put it on a black nylon web belt and carried it on my waist. It worked pretty well when I only had a vest on, but when I put on a field jacket, it didn't fit comfortably under the jacket, and over the jacket blocks all of the pockets and the game bag. I then downsized to a 7x5x2 mil-spec pouch on the same belt. It fits, and I can squeeze the essentials in there, but I had to downsize to a much smaller steel sierra cup. Canteen cup vs. Sierra cup; what say you all?

Canteen cup is heavier gauge... What kind of abuse should it hold up to? I use a canteen cup in my kit and i love it!

It's hard to have an opinion on this as only you will know what you like. It also depends on what you consider "essentials" that must fit in said cup.

My PSK container is actually a washed up campbells soup can with a spoilage lid taped in place(the kind that goes over cat food) Nothing fancy at all really. Inside are the standard signal mirror, matches, whistle, heat sheet etc

I like the size of the can because it fits easily into most pockets.

Yes, of course cup size matters...Oh, That kind of cup....As long as it is metal, it should be fine, unless you fall on it or abuse it blatantly.

Hiking I usually carry some sort of bag, often a butt pack or gas mask bag rigged with a shoulder strap, or backpack and the canteen/cup rides inside if there is room or I clip the canteen cover to the side.

I've, over the years, moved away from the Bat Belt, everything on the belt, and use of military load bearing equipment where everything is hooked onto a harness or vest.

The belt or harness systems are intended to keep the gear with a soldier or police officer in danger. It is a concern but carrying a pack or bag I've never been separated from it. I have sometimes attached a lanyard or cord to a pack that is tied off at my waist if I ford a river or think there is some risk me and my gear might part ways. A few of my bags and packs have a lanyard sewn in with a sturdy clip at the end that makes attachment quick and easy.

I do use lanyards. For example in my first-aid kit the flashlight, SAK, and EMT shears are all on lanyards clipped to the bag.

Okay, when I first saw the title I confess I nearly blew Shiraz all over the screen. "Nah, what really matters is the glint in her eye." But now that I've winched my mind out of the gutter ...

I think the absolute minimum size for a wilderness cup is a pint (500 ml). Especially in winter, when you may be melting snow and fire is not always easy to come by.

If you have two smaller steel cups (or tin cans) you can alternate between them, with one melting snow or boiling runoff, and the other cooling off to fill the canteen or make tea/soup. A very practical arrangement given the need for ongoing hydration in winter.

I have a couple of those military canteen cups and they are outstanding, but they are also very heavy and bulky. While sturdy and effective, they are also rather tempting to leave at home, which doesn't help you at all.

In the past I have used enamel-on-steel cups, which are a bit lighter but just as bulky. Though I had one with just enough room for a Svea and several packets of Earl Grey -- perfect for long daytrips.

As for Sierra cups, the oversize version (16 oz / 500 ml) is quite useful, though it's hard to fill them more than 3/4 full over a fire. You can wire them to a longer stick for a handle. They pack up very compactly. And don't forget their classic function -- slipping the handle of one or two under your belt as you "just stroll down that trail for an hour to see if there's anything interesting down there." Nice slim profiles; you won't even notice them until you need them.

I'm glad that I'm not the only one that did a double-take at the topic title...

But seriously folks, any suggestions as to cups that fit around standard 32 oz Nalgene water bottle?

i use the GSI Glacier stainless bottle cup/pot: GSI single wall 18 oz.
fits nicely around/under the nalgene. fills the nalgene in two pours.

a note of caution, your pack, if attached to you and then you lose your balance and fall in, might pull you down and under.

i too, like you, have the important things tied to the pack exactly as you described. but when fording, i'd undo the pack's waist strap and sternum strap. i figure if i fell in i'd let the pack go and save myself first w/o the extra weight. then i'd go look for the pack. ymmv.

I never understood why people were so obsessed with canteen cups.

I drink water right out of my water container (usually it would be a 2 liter pop bottle) and if I need to heat something I have a small pot or mess kit for that.

I can't say what I would do these days exactly because I have not been hiking in a while, but I usually had a plastic insulated mug with me for hot drinks. If I go to the trouble to heat water to make hot coffee, I want it to stay warm until I am done drinking it.