I've always liked the C2 case from Bic for my mini-bics.

http://www.bicworld.com/us/products/details/232/c2-metal

It seems to be less bulky than some of the other alternatives and I got 4 of them for free as part of a promo several years ago. They do add a bit of bulk and weight but I figure its a good trade since anyone who comes across this in my kit will be able to get to the lighter and put it away without going what the heck is this thing for.

- Eric