FenderBean,
Talk to Scott at brillelli engines and he'll give you the information you are looking for even if you don't buy an engine from him. Brillelli makes quality engines and has the best customer support you will ever find.
I know they have flown a Christen Eagle with one of their 46cc engines and it flew well, but only Scott can tell you if it has the power you are looking for. Brillelli is going to release 2 new engines a 54cc and a 60cc and I know one of these would do the job. I am waiting for the new 54cc engine to go on a 80" Cap-232 I have. The best thing is these engines will cost you about $200.00 less than a DA50. Here is their web site. Give them a call or send them a e-mail you won'y be sorry.
www.brillelli.com