I have used deal extreme tail lights with pretty good results. http://dx.com/p/bicycle-bike-2-mode-...2-x-aaa-120031

This is obviously a superflash knock off, as are the ones I have previously purchased. Though the ones I bought a couple years ago didn't look so blatantly like a PB product. I have owned deal extreme tail lights, PB superflashes, and radbots (as well as dinotte, cateye, and others). The deal extreme lights have held up as well as the superflashes, but not as well as the radbots.