You realize it is possible that more conservatives simply identify themselves as independent these days. The Republican brand took a beating in the last few years of the Bush administration. More right leaning folks (such as Tea Party supporters) self identifying as independent now would explain why polling shows so many more Democrats than Republicans, AND it explains why Romney is winning the independent vote in so many polls. It makes pretty good sense if you think about it.
I'm going by the RCP average which has been very accurate the last 2 presidential cycles (basically since it started). It has Romney up .6 at this moment in time. I'd bet the election will be within 1 percentage point of the final RCP average (as it was in 2004 and 2008).
According to Rasmussen, R’s are a much higher percentage (~36.8%) than they were in 2010 (33.0%), and 2008 (33.4%). This would suggest that most of the Independent gains have come from the democrat ranks.