Correction and clarification: which of these states do you see swinging at least 15% toward Romney or away from Obama in the next two months and 5 days?
(August sort of got away from me. It doesn't feel as if it's already almost over to me.)
Or do you reject the numbers Remirol cited?
I though Remirol gave a very good overall analysis. Republican nominees nowadays have to really thread the needle to reach 270.
Personally, I agree with the prognosticators who feel that independents/swing voters will break hard towards Romney at the end. IMHO, there are a lot of people out there who don't pay any attention to politics until right up to election day, then pull the lever based on the oldies but goodies: "Is the country headed in right direction?" and "Am I better off now than 4 years ago?" Polling on these questions shows a strong "no" for both. The question is, will voters hold Obama responsible or agree with him that the Republican House has caused the problems by obstructing his agenda? My guess on this question is reflected in my EC prediction in the OP.
Specifically regarding the 5 states you brought up (OH, WI, VA, IA, NH), I have New Hampshire and Virginia going to Obama. I think Iowa will return to a razor thin margin like it was in 2000 and 2004. They have not had the demographic changes of, say, New Mexico and I think their 2008 result was fluky. I put Wisconsin in a similar category. Republicans have had success there recently, the demographics have been relatively stable, and although they have gone Democratic for quite a while, the 2000 and 2004 results were extremely close. The ground game still in place from the recall elections + Paul Ryan could put them over the edge.
That leaves Ohio. Romney's biggest target is of course Florida, but Ohio is right up there. A loss in Ohio would probably require him to pull off a stunner in a place like Pennsylvania or Michigan... and if he loses Ohio, it almost certainly means he lost decisively in both of those states. Current polls have the state in a tight race. As with Ohio and Wisconsin, my guess is that the late break towards Romney will give him the state.
ETA: It really wouldn't take a radical shift for some of these states to go for Romney. For instance, Remirol had both WI and OH at about a 70% probability of going to Obama. The polls in both of those states are actually quite close - the latest RCP average puts Obama up about a point-and-a-half in both.