Python Form Processing alternatives
Is there a more specific reason you don't want to use django.forms? I've quite successfully used bits and pieces of django all by themselves without trouble in several projects.
As an aside, there are several patches that make django sortof work in app-engine, though I assume you've considered and discarded them.
django.forms is very nice, and does almost exactly what I want to do on my current project, but unfortunately, Google App Engine makes most of the rest of Django unusable, and so packing it along with the app seems kind of silly.  
I've also discovered FormAlchemy, which is an SQLAlchemy analog to Django forms, and I intend to explore that fully, but it's relationship with SQLAlchemy suggests that it may also give me some trouble.
Is there any HTML Forms processing library for python that I haven't considered?