Seen a couple in action the filabot was fairly impressive.

But given just how much filament I can buy for that kind of money, and also given that it's much better quality than the stuff I'd be able to make and the fact that commercial filament is getting cheaper all the time.
I just don't see a mass market for this kind of thing.

Okay you've got your treehugger vegan types who actually believe they can make a difference by doing this kind of thing - but they're (thankfully) pretty scarce.

Good luck with your project - but were it me I'd be looking at something else to actually make money as a business.

A cheap add on laser engraver/cutter to fit any standard 3d printer - for example. I'd like one of those.