You're not gonna find one advertised by a manufacture cheap. You're gonna have to get a local machine shop to make one for you. And even if you do that you will need to find a shop that has already made some and know what you need or they will charge you a ton.
If you can't find somebody call Scott at racinginthedirt. Super good guy and will make anything you need. He deals in custom made 4 wheel drive parts.
http://racinginthedirt.com/
He used to keep an add in the mud racers section on RJ, but I didn't see it this morning.
If you do call tell him I sent you.