Sounds a lot like the marketing of the high end electric ski gloves I just bought my wife for Xmas(no she doesn't look at these forums). Well, if your going to do heated grips they look like the top dog. One key issue though, they are a DC system. The bulk of the Beta's stator output is on the AC side. The DC for charging the battery is from a different winding with a much lower output. You have two choices:
1) convert the entire system to full DC, requires stator mod (float ground) and a higher capacity rect/regulator.
2) build a secondary DC system on the AC side. Additional rect/regulator, and filter capacitor. This MUST REMAIN ISOLATED from everything else including ground. I may do a similar system for an LED light bar.
If your planning to dual sport where you may want DC for other apps like GPS then option #1 is the better plan.