I use Piwik to track my WordPress visitors and my RSS feed separately. Of course I need different widgets for my RSS tracking (like: no “search” related things), but Piwik does not allow me to use different widgets per website.
Well, yes. I can try it shortly: If you add two “sites” to your Piwik installation, both sites will have the same dashboard layout. I wish this could be changed.
You can do something like this by having two different login IDs, one for each of the two sites you wish to view. The dashboard is separately customizable for each userid.