The biggest issue with Iris Pro isn't availability, it is cost. It really isn't more cost effective to use over a discrete GT750M..... as far as AMD APUs go, I don't even put those in the same category as the 750M and Iris Pro.
Most of those chips are LGA and the mobile versions are cut down so much and don't perform nearly as well. I mean look at the chart posted above - the A10-5800K is a LGA desktop part . I don't think AMD has any APU that is in the same ballpark in terms of BOTH performance and power use for mobile. Iris Pro is designed for mobile, and these A10 chips aren't. So it's pretty stupid to even compare them.
So this begs the question: which mobile APU fits in the same power budget as the Iris Pro and performs the same? Not a single one. Then again, you could point at the price tag of the Iris Pro which is the reason it performs so much better than AMD's mobile APUs. The only one comparable in terms of performance is an LGA desktop part. Unless the argument is that Mantle is the performance equalizer for AMD APU's to bring them to parity with the GT750M or Iris Pro for mobile gaming. I dunno. Seems like a long shot and I doubt it, but i'll hold judgement until Mantle is here.