I think your really going to struggle to find a spot retail broker being a US citizen and your only options are to offshore with either fxcm, oanda or forex.com. Be aware these guys may be counter party to your side and I've had issues myself with money going missing so I would be extremely careful in putting all your funds in the account just use the high leverage with the smaller trading account to protect yourself. Have you thought about futures?
Thanks for the reply. I'm confused though. I figured worst case scenario I could just open and FXCM account. Why, being a US citizen, would I not be able to trade spot FX on an FXCM account. They have an active trader qualification that lowers commission rates it seems (still $18/million which isn't great but better than $40!). Why do you say my only options are offshore?