Hey Famograham, I currently fish out of a 10' inflatable with a 4 horse, and seem to do alright. It is a little light, so it has a mind of its own regarding direction with the riggers down, but it still pulls them along. I say you can fish from pretty much anything. And, following up on another post, I once saw an outboard mounted on a foam block in the Fraser. The bottom line is, there are lots of affordable boats out there, so pretty much any one can have one. Just make sure the one you pick is sound, and know its limits.
I gotta get a pic of mine up here and put the rest of you to shame!