The reflector fact could be a problem, for the ones willing to go more of a DIY route (splitting the head light to install), you could install 4x 3w led in series each with a cone on them (45 degree linked below) and run them at 50~66% rated current. Probably would be best to have 2 at a wider angle, and 2 shorter so the sides light up well.
2pcs LED Lens for CREE Lumens Seoul 45 degree Matte | eBay
Don't forget current limiting in the design or you will burn them out fast, and sites suggest ~10in of heat sink surface area for cooling a fully powered 3w led (700ma) I would be planning to run at around 350-400ma so around 1/2 that should be about right for me.
Now I don't know what I want to try first lol, similar 6w led headlight lamps for my car are around $30 per pair or I already have 40 3w LEDs but not the cones or drivers/1-2w resister. Fun factor and learning experience is priceless though for me
