I was just in a, ummhhh, a sort of, ahhh, counter culture shop.
I found a black tin 4.25" x 3.125" x 1.125". They had designs on the front that looked just like the leaves from a Japanese maple, a personage who I was told is one "Bob Marley", and multi-coloured, fractally toadstools. The one I picked up had a black and white optical illusion design of muchrooms on it. My goodness, what an unusual shop.

Okay all kidding aside, pretty good tin. Just a tobacco tin, with a sticker on the front that can be removed if so desired. I'm leaving the groovy, trippy mushrooms on mine though.

In Canada, cannabis culture shops are pretty common. I'm sure that in parts of the US and other districts, a veritable scorched earth policy has been waged against head shops, so they may be near impossible to find. Some record stores might carry them, maybe try that.

While in said shop I also picked up some small glass vials and some 1" zip loc baggies. Handy for small amounts of bleach, PP, tea tree oil, and small quantities of whatever pills you feel are important in your kits.

Another tin that might work is the tin that the Brunton Helios lighter comes packaged in. It's 3.5" x 3" x 1". I was pretty leary of piezo-electrtic lighters, since most of the ones I've tried have been a complete bust, but this one has stood up to two years of hard use with no ill effects.