Thinking of other hobbies, I haven't been interested in plastic models since I discovered Guillow's kits when I was 10. But occasionally I'll pick up an kit of an aircraft I'm interested in just to use as a possible reference later on. I found these kits of the Nakajima Ki-27 ("Nate") and the Mitsubishi Ki-15-I ("Babs") at a second-hand shop for about $7 each. Both would make great RC scale subjects.