We're starting to work collaboratively on different Skuid pages, and it would be nice if we could have a chatter feed within the page builder, so we could discuss edits. Seems like it wouldn't be too hard, considering that Skuid seems to be built with Skuid...
Though you can't change the page builder, you can make a local clone and ad to its features yourself.
You can build a builder that has a second tab with a chatter feed built into it. Then you just have to turn on Feed Tracking for the Pages object, and you have chatter for your pages.
To implement the new page builder, I think you'll have to create a local copy of the skuid_PageBuilder VF page that uses the new page you have created, and then you'll probably have to update the "buttons and links" for the "page" object.
Actually going to try this soon. Has the process changed now that there are Master Pages? The PageBuilder page has a master page of SkuidCoreMaster, would you have to duplicate that as well? Or can a local clone of PageBuilder still use the package's SkuidCoreMaster?