From the way I see it, at the very least, you need a bulb that has the stub at 90 degrees since the sockets for the tail lamps are below the housing. I have seen these types of bulbs out there, but my concern follows next:
I read that the thermal flashers are not heavy duty enough to flash the led bulbs, and that you would have to upgrade to an electronic flasher unit. I would have to recommend more research on this to verify.
Lasty, I don't see paying the rediculous prices for these set-ups. I bet with some additional research, you could find a how-to on the web with parts you can get at radio shack.