There is LayerByLayer.com but it only works on makerbot's. Then I find it problematic that, as a designer, you don't see how many times it has been downloaded same as on shapeways by the way. LayerByLayer.com works problematic for the customers, I think and they don't trust them. I bought the URL: iSellMyStl.com but am not a developer and everybody is on the same quest so I'm first trying to find out where the problems are. Interested developer wanted!