I recently purchased and Emotiva RPA-1 and am happy with it. The Outlaw amps also look good, although you'll just need another power outlet for two of those. Two Outlaws would be $624 with free shipping. I got my RPA-1 for $630 with free shipping on a special, and they'll probably be running another special before next spring. So, cost-wise, they'll probably be nearly identical. I like the modularity of the Outlaws, but I also like the looks of the RPA-1. Hard to say which I'd buy if I were to do it over again, but I think that you'd be happy with either.
There was a thread here recently that referenced an article on the Axiom website about receivers and their 4-ohm speakers in which Axiom was saying how certain brands weren't really up to it. I can't remember the brands, but you might want to look at the Axiom site (or search here for it) or give them a call/e-mail. The Emotiva RPA-1 would have no problem with the 4-ohm speakers, nor would the Outlaw monoblocks.
Adam