Ben,
As for engine choices don't neglect looking at the Brison 3.2. For $450. it is every bit as good as the others you mentioned and less expensive. It get's overlooked because of the reputation built up by BME and DA in the 100 and 150 sizes but at the 50cc range it is light, powerful, inexpensive and top notch customer support.

As for airframes besides the Patty (which I highly recommend) you could look into the Wildhare Edge as the only one mentioned above that is available today. If you are willing to be on a waiting list and be the guinea pig....Wildhare Extras and Extreme flight YAK's are options. Dave Patrick recommends NOT putting gassers on this size model of his. The Chip Hyde planes are also too small in my opinion. For the money the Patty can't be beat and everything else will end up running $150 more to start out but in a year some of those others will be field tested and we'll know more.