I would think that most airframes that were suited for a single .45 sized DF and some that used a .91 size, would be OK for the Wren 44.
I remember seeing a BVM F-86 flown on the Golden West FD3/64 and it was very impressive. That engine had similar performance to the Wren 44 but was bigger and heavier.
Will Whiteside just did a YA A-4 Skyhawk ARF with a Wren 44. It worked out very well.
http://www.rcuniverse.com/forum/Yell...2440938/tm.htm