The Firearm Blog has the details. Looks pretty damn cool considering the current cost of .223/5.56. I do have a few questions though.
1. Will it be reliable with steel-cased ammo? Wolf, Barnaul, and corrosive milsurp are the only 5.45x39 ammo sources I can think of and I doubt anyone's going to come out with 5.45 brass-cased ammo. That would likely eliminate a great deal of the cost savings over 5.56 anyway.
2. Corrosive Ammo? - I really wouldn't want to run corrosive milsurp 5.45 through the AR's gas system. I imagine cleaning would be a real bitch.
3.Will S&W sell just the 5.45 follower or will you have to buy expensive mags?
This seems very promising if it's reliable with steel-cased ammo and is priced right. I'm surprised I just heard about it now, since they apparently released the info back in March. If it works well this would pay for itself within a few thousand rounds, although if it's popular it'll likely drive the price of 5.45 up immediately.