Awesome!
I had a thought for how you might expand the market for your bike.
One way you could start to open up the potential market could be by providing a modular bottom bracket "area" or "drive box" to accommodate the different types of drive systems.
So your market right now is essentially:
Home builders
Who want an offroad bike
Which uses a hub motor
DH bike geometry
It's two parts. The frame and a drive box that mounts to tabs on the frame. A "drive box" would be a mounting system designed to fit on any frame you build with 4 bolts (or something), but each drive box would be capable of accepting a different kind of motor configurations.
You would then supply different drive boxes designed for different drives, for example:
Standard BB and Crank for Hub motor
Recumpence Drive + Crank
Jackshaft Style Crank + motor (a good choice if you want to go Belt all the way)
Pinion gearset capable
http://pinion.eu/discover-pinion/pinion-p1-18/
No Crank, only a motor like an etek or mars.
Open Mounting - Mostly a DIY option for someone to retrofit their own setup
On top of the expanding the drive-type options, all your future frame designs could take advantage of a standardized drive mounting system, enabling again many choices for frame design from road to recumbent, or DH to Supermoto, with no extra drive-design work.
Something like this would cost more to develop for sure, and is probably not good to even attempt right now, but seeing the variety of bikes here (and my own odd tastes), it could make your frame a much more viable option for a larger market of builders - myself included.
SHiFT