This could be done compactly with a tube which zig-zags from a larger bulb. Then the scale of tens of degrees could be along a side at one end of the zig-zags and marked but unnumbered degrees marked on each horizontal tube (since some scales would increase in one direction and alternate scales in the other). I haven't had a lot of luck in making a prototype, but it doesn't seem like a big problem for a professional shop. One possibility I haven't tried yet is to make the sig-sag out of low-melting-point wire, then mold plastic around it, then melt the wire and drain it out.
Adapting the catalytic burner principle to melting snow (and possibly for slow cooking) either in camp while I'm away, or in my pack. Melted snow or ice is the main source of water at high altitudes, but stoves seem so inefficient for this. The simple version would be a jar of snow and a catalytic hand warmer in an insulated bag. The "Crock Pot" type slow-cookers consist of a small heat source and good insulation, for which a Thermos jug would do fine. A "heat pipe" might connect it to the catalytic heater.
But now I'm also thinking about a combination snow melter and water purifier which would boil the water, then transfer the heat to the snow or incoming water, thereby producing fairly cold, sterilized water.
Several years ago I learned how to make a small, simple wood stove from a coffee can, and coat hanger wire for a grate. It needed only twigs to make a good fire. Once I even used dry grass successfully. But it was a bit bulky. How about a simple, square stove made of four flat, hinged panels, with each side maybe 5" X 7", one side with a door? It would have adjustable vents at the top and bottom of two or more sides.
A boater's jacket of "breathable" fabric, but with large zippered pockets on each side of the chest. The pockets would hold a canister of compressed liquid foam material. When a cord was pulled, or perhaps when the canister got very wet, it would burst and the foam would inflate and harden, without penetrating the close-weave fabric of the pockets . It could be removed later by dissolving the surface with a common solvent, or the pockets could be replaced.
The same kind of system would be good for boats, for instance open canoes. Space is often at a premium, especially for the feet of the person in the bow. Floatation isn't needed until an emergency, at which time perhaps bladders, mounted in the bow and stern, or elsewhere, would inflate.
I tend to avoid specialized, high-priced equipment. For instance I wear Velcro-fastened athletic shoes from Pay-Less for general use, including hiking and light rock-climbing. A better shoe would only mean more difficulty finding a challenging climb. The Velcro seems quite satisfactory for my use and I would like to find it on high-top shoes, and more variety of Velcro low-tops. I've seen one pair of high-tops, on a hike leader, but never since.
I'd be quicker to buy many products of all kinds if I had sufficient comparison information and felt reasonably able to clearly identify a good deal. Energy-using and producing products are relatively easy to compare in numerical values. I'd like to see considerably better information, particularly for nutritional value of food by weight, volume and price; light output and endurance of flashlights, batteries and bulbs; efficiency of stoves and fuels.
It's naturally a bit hard to digitize and chart food flavors, since they're in the mouth of the beholder. But for both indoor and outdoor foods, I'd like to see more foods that didn't concentrate so much on flavor, and therefore would be reserved for when they're needed, rather than encouraging us to overeat.
I'd like to see comparisons of all fuels, liquid and gas, in terms of temperature and energy content per weight (including container), volume and price. It's not enough to simply say "White gas stoves are generally termed `high output' as they tend to burn hotter than butane." How much hotter, and for how long?
It would be nice if more camping tents were available that would blend in with the environment, camouflaged, olive-drab, gray or brown to look like a boulder.
If you're into primitive tools, I've invented an improvement on one that's maybe been around and unimproved for a million years, the bow drill. The original version may work better with natural rawhide and such than with nylon cord, but this is an improvement on both. Traditionally, they have one cord going between the ends of the bow and wrapping around the shaft. Istead, use two cord, one from each end of the bow, tied near each end of the shaft. They're long enough that they can be wound several times around the shaft, in opposite directions. One winds up as the other unwinds.