I just wanted to mention here that I am currently developing a specialization of xotcl-core's TableWidget called ::YUI::DataTable, which progressively enhances the markup generated by the TableWidget.
It behaves a little bit different compared to the standard OpenACS tables regarding the form, which wraps the table. Instead of changing the forms "action" attribute via JavaScript when the user clicks on a bulk-action, I implemented each bulk-action as a submit button. The value of the button represents the method called on the object, which "sits behind" the action-url of the form.
However, this code is subject to frequent changes and currently not very well isolated. I will publish it as soon as it is mature enough (beta or so).