An EFI hybrid motor is definitely a dream of mine, or better yet EFI hybrid turbo'd... Anyway, if you're not allowed to spend the money it would cost for a propane conversion, then I would assume you won't be allowed to spend the money it would cost for a custom intake since that would probably end up being some serious dough. You could always try mechanical fuel injection. Some guy over on pirate has put together a kit using VW parts. Good luck, whatever you decide.
http://69.50.175.2/forum/showthread.php?t=516406