I've gone ahead and rewritten many internal portions of the Presentation Engine (most of these changes won't be noticed by most people - unless you are looking at the code that it is.) This is in preparation for the upcoming first release of the Presentation Engine source code.
While the first release will not be quite as user friendly as I want (at least it isnt right now), I believe it will provide MORE than enough functionality to warrant a release.
If you want to take a look at the code BEFORE the release, feel free to drop me and email and I'll send the stuff over to you. (Everything including the themes is about 900k zipped up)