Since you're making custom beams, have a look at some of the live axle stuff. There is no reason you can't weld the 'C' bracket from one of them onto your custom beams. I'd think that you can find a set-up with big enough BJ's for what you want to do. The trick might be in getting back to your bolt circle, but people like Warn have wheel hubs that should help with this. Worst case you convert to 8 lug and gain some huge brake rotors in the trade.