Serious progress? I made that impossible by suggesting it might happen didn't I?
I did force myself to make some actual progress on the CMS tonight, and have just finished implementing the SBuilder::PageType::Copy module. This is the simplest of the Page Types, and simply slurps a file and then returns it as a scalar, prints it to standard out, or to a file (either a default based on the database or a one specified as a parameter to the method). It doesn't do much but it does lay the groundwork for other modules (in that a number of the methods will be moved to a superclass).
Since the output can be to standard out or to a file, it makes it more convenient for use in a preview scenario (dynamically rendering resources while making edits with the CMS frontend).