Sure, it might seem difficult. but i don't think it requires much code. When your computer first finds out who the other players are, their callsigns, that's when your computer can also find out what .vfc files (skins) your friendlies and enemies have loaded.

Let's say, you are flying a Hellcat and decide to load the Alex Vraciu skin. All your friends online need to know is that you have loaded that Alex Vraciu skin. Then they can tell their computer to load the Alex Vraciu skin on your icon or callsign. The loading of skins is just done once in the game cycle, perhaps in the Arena Menu or Plane Selection Menu. Perhaps each player can choose to load all the other players skins, or maybe the Squadron Leader loads and distributes the skin assignments to all. If a player does not have a particular PDC skin, the default skin loads. Loading Custom Planeskins for that nights' game would be optional, just another button to click on the Game Setup menu. Click that button and you go to the kind of screen shown above.

I realize, that a scenario with 30 to 50 players online would present a possible frame-rate drop if your computer has to draw all those hi-res planeskins. Selecting 30 to 50 planeskins might be slow, but it could be an automatic thing not using a selection menu at all, just click a button:

• Planeskins On
° Planeskins Off