I didn't get an answer on my similar question, but here in the UK we have something like that in operation already - crowdcube.com

I've not used it yet myself, but I find the idea compelling because it allows people to actually invest in companies that need funding, rather than just pre-order.

It seems to support loans with a set interest rate or actual micro-equity. I might actually get around to investing through it someday...

There's been a boom in France as well in crowdfunded equity. A startup I did some work for did it, and were happy with the results.