The whole point of jQuery is to serve as a substitute for the DOM, allowing scripts to efficiently interact with page elements. If you're running this via a Python script, you already control each and every bit of your page code. What's the point? I can only see this being useful in Python for screen scraping.
Scraping with BeautifulSoup works pretty well, but i've had a lot of problems with nested elements with no id since Xpath is not available on BeautifulSoup.
Perhaps this would make it a little easier. I'll report back after trying it.
It could be used to skin an application ala deliverance. Or as a templating language: you would only write html and then put stuff into it with python and pyquery (but I think the jquery API may not be good enough for that).
Wish I saw this earler - I am already in the middle of a project (screen scraping of course) using hpricot.
Sounds weird, but the only reaason to pick ruby for me was hpricot and not RoR :)