Crosswind is not taken into account in the calculation of Vmcg because the certifying authorities consider that the chances of having an engine failure exactly at V1 are less than ten to the power of seven. When we used to fail engines during base training on the 747 we used to apply Bellerophons figure of +1.33kts/1kt crosswind to the Vmcg.
After the last discussion on this subject I decided to do an experiment on the sim. We did a heavy weight take-off on a wet, limiting runway with a 25kt crosswind from the right. The V1/Vmcg was 133kts and the Vr was 169kts. The very experienced (and willing) crew were briefed that the #4 engine was going to fail at exactly V1 and that they should apply, and hold, full left rudder. After the engine failure the aircraft yawed to the right, leaving the paved surface passing 140kts. it continued to yaw to the right although at a reducing rate until full directional control was regained at 165kts. At Vr (169kts) the SIM FRZ button was pressed and we then estimated that the aircraft had deviated about 300-400ft from the runway edge. At some airports you would be in rather more than weeds!
Airclues