Most of my emergency items are distributed amongst my pockets these days so I don't often use a tin anymore, but I've enjoyed making tins through the years, finding smaller items and spending time figuring out clever ways to pack them. Here's my take on them...
I wanted something pocketable, and water was the driving requirement for size: I wanted a tin that would fit a couple of rolled up whirl pak 1 liter bags without folding or creasing, so I didn't have to divide my water purification tablets.
The classic "SAS" style tobacco tins were the right width and length, but were a bit too thick - this limited it to a cargo or jacket pocket, and if in a cargo pocket I found I could easily fill it with so many items that it would be deceptively heavy and uncomfortably bounce on my leg. I opted instead to divide the task and found a couple of gift card tins that were the same width and length as a tobacco tin, yet also the same depth as an altoids tin. Thanks to the reduced depth, the tins were lighter and thin enough I could put them in essentially any pocket of a good pair of cargo pants.
A simple bolt and wingnut connects the carbide sharpener to the leatherman saw to serve as a handle.
I've since made significant changes (Sierra saw blade, more cordage, multi-tool, mosquito headnet, etc) but haven't gotten around to taking pictures yet, I'll see about doing so this week
The paradox is that those who think to put together some sort of survival kits are also often the least likely to find themselves in a situation in which they would need one!
We do a lot of water related rescues, and while I have a bag in the boat I wanted an emergency shelter on my person in case I get separated from it. For that, I usually have a palmer furnace setup in my cargo pocket for all seasons except summer to serve as an emergency hypothermia shelter, and an emergency FAK in my other cargo pocket. Other bits and bobs include a PLB and mini orion signal flare on my PFD to supplement the other firestarting items (I usually also carry a Bic mini in my EDC, but if you're cold and wet a flare is nice)
Nothing fancy, but it worked pretty well in my testing down to 0C. The poncho is the same material as the SOL heatsheets, so it's a little tougher than most mylar blankets and has a reflective liner. Rubber bands are for closing the arm holes on the poncho. I've since added an inflatable xerovest.
If you store the candle with a bit of fluffed up tinder quik on the candle wick, you can light it with a spark which I'd imagine is nice if your hands are cold