@Expertise87: Thanks! I've never actually gotten this far in a real game. In practice, I've always seen 8.Ne4 (instead of 8.cxd4), to which I play 8...Ne3 and end up a pawn down with good play against the backward d-pawn which usually falls in the end.
FWIW, my repertoire move in this line is 11...Rb8 which seems a lot more useful for Black than 11...e4 played above. Do you know of a refutation for this particular line?
This is one line I think gives Black unsurmountable difficulties.