The idea sounds great, there is one problem though, this map sounds like it would include lots of people, you might not want to use any units not included in the official pack so the masses of normal players can play- unless computers are on each side, then you can have all the addons you want.
I have an idea to add. When you die, waiting 30 minutes will get very boring. How about when you die, you spawn as a civilian (also you can start as on). When the next shipment of troops comes, you can choose to stay as a civilian for a bit longer or go back to being a soldier. The civilians can try and get people for there cause- remember Russians and America can be civilians (troops can do this to the human all time civilians) - As you see, civilians will fall in different groups and get supplied by different armies. The civilians will turn into "gangs"- for example, there wouldn't always be two sides. Some might want to get all countries off the island, some might want to rescue the hostages with the Island government, some players might band together to shoot who ever they see, some people would stay solo until they found a team that looked to be the strongest, and so on...The civilian thing would make a great mission alone... anyway, when you die as a civilian, well you will just have to enjoy the seagull life for a while.
Oh, and one more thing, I think the BAS rangers would make great U.S. soldiers.
OH! Instead of a plane, you could use a "mech" from the BOH mod- the Japanese mod. You might want to lock it to keep the nations even...or some one could unlock it.
...if I wasn't clear enough, just tell me.