I'll have to look at this a little more. I think it's possible, but I need to see how much code needs to be changed. Just so I am clear, I'm assuming you are using the 1.0b3 release from the public download link and not the current SVN code that has yet to be released, correct?
ETA: Just clarifying that you want this for albums only and not collections as well, is this correct?
Sorry, just albums. The collections I'm using are 'active projects' and 'archived projects'. The albums are a photographers current projects which will need commenting on. If the commenting can be switched over, I may try adding a rating system in there too. I just don't know the core code enough to move commenting.
Would it not be possible to add checkboxes in the admin 'options' to choose whether to be able to comment on collections, albums and pictures? Say a checkbox for each one??