There are a few transdermal patches out there for vitamins. It's restricted to water solubles, and you have all the wonderful concerns with DSMO (like don't go swimming in gasoline, don't let rattlers spit on you, all that weird stuff), but if they give you the dosage you need they might work for you. I can't image they are temp sensative or bulky.

http://www.supersavermeds.com/vitamins/patchinfo.html

If it's C or B-complex you need with your meds, these might do the trick.

If not, you can get short, plastic test tubes with locking caps that are about the same size a shotshell. I'm not sure if there are Rx vials out there that are the same size, but there are latching test tubes out there this size for things like cryogenics. (Your doc might have a source for them via labs.) If not, ranger bands along the lenth of the tube and over the cap. Label everything properly, slide it into a shotshell holder, and you can have up to 12 tubes in the old-style ALICE carrier. Or go Pancho Villa style with bandolers. <img src="/images/graemlins/grin.gif" alt="" /> (and I really hope that was really a joke on my part- if not, I'm sorry)