From the sounds of it, two very interesting projects and concepts for you web UI folk to consider. I don't have time right now to personally look into it deeper, unfortunately.
I suppose I should have known this... Andy McKay just informed me that this is a standard feature of table listings in Plone, even in Plone 1. I tried it and it didn't work in Safari, but it did work in Mozilla. Very cool. I wish it worked in Safari, though.
Thanks for the info Andy!