I believe, memory, that the SandCrab was a single engine turbo prop, rear, that was developed for an Arab country. It was last reported in Arizona, USA. The twin was developed by Bassler, in Oshkosh, but I don't think they ever made any.
For more information, look at
http://www.superskyrocket.com/pages/...istory_1_1.htm
It's on the riley website, and there are several pages of history there.