I think the ESC that is fitted to the Slash 4x4 has a lipo cut out, I should be able to tell you more soon as I know a man that has one on the way.
I enjoyed a quick blast in a Slash (2wd) despite it feeling terrible slow with the stock motor, on the plus side it seemed pretty darn robust to me!! With a 10.5 in it it will be a right hoot
Saying that I wouldn't swap my SC10 for one