Heres my basic rustler from awhile back...
http://www.youtube.com/watch?v=emDnnbfJEGc
ESC- Hacker Master Car Sport
Motor- Feigao 8xl
Battery- FlightPower 3200mah 30c-60c 5s lipo
Gearing- 21/48
Before and after pics...
Before
After
I hit 68mph on one of the runs but I could have gone much faster. It was geared for casual fun in that vid plus I didnt have much room to cope with for good speeds. I would have bet that with the right conditions and downforce on the front along with proper gearing that I could have hit 80mph+ pretty easily.