I bought these a couple of years ago - Come in a nice bag.

http://www.amazon.com/gp/product/B000LQ78YY/ref=oh_details_o02_s00_i02?ie=UTF8&psc=1

These actually run off of AAA batteries, which are easily available, but probably not as good as the CR123 types due to battery life expectancy. I've tested these, they are surprisingly bright and have a couple different flash patterns IIRC. Very Durable.. Apparently you can run over them w/o too much damage. At 1/3 the cost of your other ones, I think they might be a viable alternative depending on your needs.

I always figured if I went down in a ditch or my car was stranded in a blizzard etc, these would be a good beacon of "Hey! There's something here!"... (Please don't rear end my car!)

Rod