I've used that exact same setup in the past for larger websites (+500 pages), in combination with SSI for header/footer stuff. I'm not terribly worried about the sites that need constant work or are large projects where we have to allocate alot of programming man-hours, since those usually have small design update issues.

The amount of effort put into changing 1 single script tends to be alot more than changing the entire site look and feel, and that's where we hit the hard cold bottom. Smaller sites shouldn't require a programmer's man-hour (which is more expensive than a HTMLers man-hour) when the maintenance is purely synthetic.

I'm rambling... What I wanted to say is yeah, I like your setup and I've used it in the past, but I'm looking for a solution for the smaller, everyday sites (40 pages tops).