Haha, well if we offered one you know we'd be hawking it to you!
Roof is a complicated shape and with possibility of doors involved, there are a lot of design factors to take into account. We won't be offering one, we looked at forming a cab system from ABS. WAY too complicated of a shape and we couldn't come up with a way to do it in his shop that produced a finished product that sealed well, looked like a professional piece, and that wasn't more expensive than Honda for an Apples to Apples product, and I personally won't stand for selling something that while it's very functional .... Looks like JUNK.
Only one I've seen that I liked the design of is the FTD, it seems sturdy, well made and if you're not planning on a full cab with doors, a great design, doors are complicated.