The nice people over on Reddit.com have linked to McCain's full 2008 file on Mitt Romney.
Reddit thread about it:
Scribd copy of it:
The Google Docs version:
It includes a great deal of flip-flopping and actions that the right-wing won't like (things like increasing the cost of gun permits and raising various taxes.)
This could be a good resource of info, as it usually cites the sources if they are things like newspaper articles, or cites his support for changes in laws, etc.
Hope this helps!
EDIT: It turns out that this isn't a new thing - it was released previously (I was unaware of it).
In the Reddit thread, somebody linked to this articlefrom Jan. about it: