I have also been craving a rose cut, but have been intimidated by the sourcing process. It seems that they are mostly sold by antique-style esigners in complete pieces (CvB -but I think she is willing to sell ones she has loose--, victor barbonne, etc.) OR by a lot of international, mostly Indian, vendors on ebay and etsy and the like.
I think you mostly want to look for a high dome to combat some of the transparency of the cut. And of course clarity. The problem that I have seen with a lot of the cheap international vendors is that their stones are very flat