Not a Stemme S-10, although it's a good compromise between an aircraft capable of touring and an adequate performance glider. I offended an owner by suggesting after flying one that it was almost as good as having a glider................
Currently either the Eta or the Binder EB-28, both of which are self launching 2-seater sailplanes with a best glide (engine off
and retracted) in excess of 60:1
EB28. The 28 is for wingspan in metres.
However, while that answers the original question,I don't think it's whet the thread starter meant.