Large foamies are hard to do? I guess you haven't heard of Dave's Aircraft Works 3-meter all EPP sailplane!
I've flown and owned Coroplast AND EPP planes, and they're both great. If I was going to go electric, I'd use EPP. Nitro I'd go Coroplast. BTW, I also own a Highlander two meter all EPP sailplane. That's 78 inches.
The structure needed in an EPP plane isn't that hard to make; it's usually just some carbon rod or tube spar(s). The fuselage doesn't normally need any more reinforcement than to be covered with Ultracote.
Let your dreams be the limit!
Jeff
ORIGINAL: greenboot
I didn't mean to say EPP isn't durable. You are right, it is indistructible! Making a larger plane is out of EPP or any foam is difficult. That's where coroplast is better.
I would also recommend using 4 channels right from the start. I just don't see any reason not to have ailerons. That practice goes back to the days when radios were expensive.
Tom