Quite Frankly, I carry my own. Usualy a "factory" kit does not tailor the thing to your needs. I fly over water a lot and use the adage that what your not wearing may not be recoverable. I carry a mirror, strobe and a spyderco on me. Usually an ICOM in a plastic bag in my pocket. Wish I could convince the company on a Satelite phone.....but they are more expensive to replace than I am.
Think about where you are and what you may need, then build your own. You can find all kinds of goodies with a little imagination and the internet. Companies Like
www.pelican.com and many others that folks here will tell you, supply items.
As to your own resourcefulness take a few old CDs and throw them in, they make cheap signal mirrors.