I thought the PBS TP100 @ 241 shp would be the ideal partner for an LNC2.  The airframe would requiire some additional tankage (the turboprop consumes about 18gph at cruise) but I'm sure someone serious about the conversion would find a way.  Engine and prop combo weighs in around 230#, The attached photo is the first flyable engine from the factory being fitted out on Diemech's RV10.  FWIW.