Skymaster & Fei Bao Jets make Vipers in the size you are requesting. While both these companies take years to test and develop a sturdy and airworthy jet, FEJ cuts out the R&D to get their jets into market within a few months. FEJ has their customers unwittingly do the R&D at their own expense.

http://www.fbjets.com/index.php?Page=58

http://www.skymasterjet.com/viperjet.htm

Sorry about your loss of money in dealing with FEJ. You are not alone.