There were actually meant to be 4 versions of each map for island capture but for some reason Eidos cut the huge versions out. With a little persistence I was able to replace the missing files and fix a number of bugs to get these working for the PC version. You can download the mod from here.
All players must have it for mp. But I then would think it should work. The only problem with MP would be unit and base distribution at the start of the game does not function. But players can spawn from friendly bases and capture their own so its not a real problem.
This modification was tested in Single Player Skirmish Mode and it works fine.
Let me know how you get on.
You can contact C06alt using our forum or you can send him private message.