Great minds must think alike. A buddy of mine that does RC airplanes and slot cars and 1/18 scale sprint cars with me said the same thing. "You need to find a small motorized tank and use the base from that for your crane"
I already feel like a cheater by simply converting a diecast, instead of scratching it like the rest of you guys!
That dozer I bought is gona be tough though, boy is it small. I may look for a D11, there has got to be more space to work with in the high drive model.
Jim