I haven't done much building lately but I have been converting glow planes to electric. Here is a sport carrier I have had for years, a Berliner Joyce OJ-2. As a bipe high speed is not real good, but it is easy to hang. As a glow it has flown with a variety of engines, most recently a FOX MkV plain bearing combat convert to throttle operation with a ST carb. The motor is a Turnigy D3548/6, 790 Kv. I'll be able to fly with either a 3 or 4 cell battery. The motor also comes in a 1100Kv version. (there used to be a 1400 but it is no longer offered). The motor is larger than needed, but when converting a glow plane balance sometime is a issue, and with this model I knew it would be. So I used a heavier mount and bigger motor to get some nose weight. It looks like the balance will be just about right. Since most of my flying is off grass these days(thanks FAAjavascript:void(0)) I'll add some bigger wheels. Even with the 4s battery I will be within the 3.5lb limit. I'll let you know how it flies. It should be fine, I recently converted a Henschel HS-123 which is about the same size and it flies very well. Although not for carrier I can hang it.
PS excuse the out of focus pictures, my camera no longer focuses properly