What about someone like Ted Turner? He has a giant ego, yes, but he's quite hands-off when it comes to running teams (not unlike John Henry, right?).
I'm not making a particularly serious suggestion, just trying to think how an American billionaire somewhere or other might be thinking right now. As someone pointed out elsewhere, Tim Howard has singlehandedly won support for Everton, so what can be done to tap into that? Buying a couple of good young American players would help. Developing a youth feeder link would help. Money doesn't come for free, though, so to earn the bigger money means being willing to tie into someone's dream.