Hope it's ok to link to my post in the mtbr commuting forum... I couldn't decide whether to put this there or here. It's a "DIY-lite" project... very little mod work required, so it didn't feel appropriate for the DIY forum where people are soldering their own LEDs, etc.

Here's the post:
$65 Dinotte 400R alternative? (headlight as a tail light)

And one image of the mounted light: