seriously, if i was starting over with motors and esc, i'd look to turnigy stuff at hobby city and go brushless. don't quote me, but i think you can get a dual motor/esc setup from them for right around $150.
brushed motor choices are getting fewer and further between, and an esc with reverse that can handle decent mod motors is even harder to find, and they ain't getting cheaper yet. william g posted a neat idea of using silver cans and just bumping up the voltage, but you still need an esc that can handle the voltage.
my ebay zilla 2 came with a tekin titan and clodzilla hopup motors, so i'll clean them up and try them out, but as soon as problems arise, i'm going bl.