Update: It appears this conversion kit is no longer available.
EV Drive offers a conversion kit to take your Honda CRF250 and make it electric. It will be interesting to see if these model specific kits can take off. Currently, the prices seem a bit inflated, but when you get into replacements for model specific kits, you’re certainly dealing with a micro-niche market.
http://www.evdrive.com/prototypes/evdrive-trains-for-e-motos-the-e-motocrf250r-conversion-kit/