I did actually do some sort-of-related work in this area, which I presented at PyCon DC 2004 - you can access the paper at
http://www.python.org/pycon/dc2004/papers/18/Setting_A_Context.pdf
An audience member mentioned the Smalltalk and Scheme-based work on web continuation frameworks, and I was sorry my answer at the time seemed unduly dismissive. There are some interesting similarities, and though my own implementation is decidedly clunky I like to think the paper explains some of the advantages of maintaining state and why the "back" button is an obnoxious anachronism :-)
I think the technique you talked about is an easier way to achieve a similar goal as the continuation-based frameworks. While using continuations for web applications is an interesting idea, I don't think it's been shown to be successful. It's certainly not something I'd want to implement on Python (even given the actual features to make it possible), and from what I've read of the Ruby projects that use it (Borges and Wee?), they aren't ready to implement production applications either. The technique you present could be implemented on any framework, right now, with the expectation that it would work in a production situation.
-- Ian Bicking / [EMAIL PROTECTED] / http://blog.ianbicking.org -- http://mail.python.org/mailman/listinfo/python-list