AndyMark's LJ Bevel Box seems to fit your bill pretty well:
http://www.andymark.com/product-p/am-2622.htm
I can't speak for the power requirement, seems like everything else is right on the money.
Alternately, 33 Killer Bees posted a pretty neat Instructable earlier in the year on how they adapted a Versaplanetary and a Dewalt 90* drill attachment for a right angle transmission:
http://www.instructables.com/id/90-D...netary-Gearbo/