The Verdant isn't actually the first time this has been done.  A Toronto-based developer Tridel did this same sort of condo loan (they called it a "green loan"), which was funded by the Toronto Atmospheric Fund.  More info here: http://www.naturallybetter.ca/commitment/greenfinancing.a ...

It should definitely come to the US, there are no institutional obstacles.  The challenge is lining up the financing.  Its awkward for someone to fund  green improvements who isn't the main construction lender...and most construction lenders don't have this on their radar.

Windmill, another Canadian developer who's starting to enter the US market, is also looking at these loans...exciting stuff!