If you aren't looking at an all-out aerobat like an Edge-540 then I second the Super Sportster. Both the .40 and .60 size fly great (own or have owned both), more agile than a 4* but not on par with a Yak. The giant scale version should be great too. That's just and educated guess of course, I have never personally flown the big one.

Another option might be a 4-Star 1.20 with a small gas engine.

There are some nice big Cubs in kit and ARF form too.

Graybeard... have you had a chance to fly your friends Sportster? I like the smaller ones a lot and I've always thought about getting the big one.