would it be at all possible to fly combat with a rear faceing prop? such as the firebird and aerobird have? i imagine that you would just have to fly close enough to the ribbons to get it all the way to the prop.

Actually, most "cuts" or "kills" are done with the wing, not the prop, so I don't see why you couldn't.

Depending on the event (it's illegal in some) guys put some type of sticky stuff on the leading edges to help score cuts.
Dennis-

how do you cut the ribbon with the wing???

i've never see or watched combat so i don't know much about it.

You don't cut the ribbon with the wing. You snag it and rip it off the other plane.

Most of the people who fly combat are using something on the leading edge (like Honey) to make the streamer stay long enough to break. At the speed the planes fly, it is hard to remove the streamer with the prop so long sticky wings are the main weapons.

A purpose built combat pusher would have a few advantages in mid airs and crashing. The prop wouldn't be as likely to slice up an opponent's wing, or break your engine mount out of your fuselage if you hit the ground.

However, here are some disavantages:

1) need for pusher props. harder to find

2) launch technique may need mods. With a conventional "tractor" config, just point up and let go. Most electric wings are first thrown and then powered on. Can't do this with gas.

3) goofy exhaust direction. Mostly cosmetic, but still a consideration. Tuned pipes and mufflers would point forward.

4) pusher configs sometimes suffer cooling problems -- especially in cowled scale applications. You don't have the high pressure blast over the cylinder like a tractor config.

would some doublesided tape work as a sticky enough surface??

Yep, that's what I'm using lately. I have a 2" roll carefully sliced in half to give two 1" rolls. Wish I could find one this narrow ready to go. It's very sticky and hard to remove but lasts an entire contest.

I also clean the tape to "re activate" it with ammonia/alcohol/soap mixture when it gets many streamer bits and grass stuck to it.