Exactly on the last point : since I'm looking to have a 'build script' working with just the sort of WP frontend / Pylons (or RoR) backend that you're doing, I

Exactly on the last point : since I'm looking to have a 'build script' working with just the sort of WP frontend / Pylons (or RoR) backend that you're doing, I created a Wordpress plugin WP-Templatize that will put tags around important WP elements. Then, to rebuild the backend template, one can do a 'curl' and then post-process using a script. So when the BizPeople change the layout, one can regenerate the backend template immediately. It's on GitHub : contributions (of code) welcome.