Foam can take quite a bit and even if damaged you can easily repair that. Multiplex has a very successful model, the Multiplex EasyStar. It has a motor mounted just after the wing. Therefore the foam nose gets all the impact and the prop and motor is well protected in the back.
This is my latest implementation. I started creating the 24" version of the Blue Baby (over)powered with a 24gram bluewonder 1300kv. A lot of rainy/windy days so it didn't even fly to get it's next transformation. A 10g, 2000kv motor pushing with longer nose for counterweight. The 2s rhino battery has to be placed as far on top as possible to counterweigh the 10g motor and 3,5g servo's so far aft the CG. The final touch of a small keychain like camera makes this a great FPV/AP aircraft.
As you can see on the images the motor has quite some down thrust. This is to neutralize the nose down effect on full throttle. In a perfect setup the shaft of the motor should point towards CG. And a good starting point for the CG location on a custom design is at 25% of the wing chord.