electric rtfs are usually small, trainer-park flyer type planes that do not require 4 channels. they use 3 because it is cheaper and it still works fine. I am assuming you are talking about park flyer size to 20 size? if that is the case, i would just get the plane you want in arf form and put in the gear you want. arfs of that size have very little building required. mostly just gluing on the stabs and installing the gear, and that is it. if you insist on nothing but a good 4 channel rtf electric, you will find that you are extremely limited in choices whereas there are hundreds (literally) of different models in that size to choose from to fir your taste, and you will also be able to put in the gear you want. rtf electric stuff is usually very underpowered. you may want something with a little more power, or an esc that can handle lipos because most rtf ones will not come with an esc with a cut-off or maybe you want brushless. either way, your best option is to get either a foamy, (practically no building at all) or get an arf (mostly just gluing) and install the stuff you want.

however you can check out www.parkflyers.com and see what they have there.