Vignette's CMS has offered this functionality for years in the commercial enterprise space, and Adobe/Macromedia Contribute has offered this functionality for years in the commercial consumer space.

That's actually kind of a neat idea. I think the word widget might be appropriate in there somewhere.

I wouldn't use it, but grandma might. And there are lots of grandmas out there!

AFAICT, this idea is for a CMS that offers in-place editing of key content areas or design elements.

O'Reilly OSCON, wrapping up Friday, had two exhibitors showing open source CMS products with in-place editing: 'Concrete5' and 'PlainBlack WebGUI'.

Cool, I'll have to check those out. I was selfishly hoping that something like this is already out there.

Thanks for the links - I checked these out, and while they are cool CMS products, it's not quite what I had in mind. I'm not looking for a full CMS system or framework, I just want a simple library + compiler that can plug into any existing site that is not built on top of a CMS backend.