Have been doing quite a bit of work combining jQuery Mobile with Django for certain (internal) projects. You can set up the JQM stuff with a few lines in your template, then mostly "forget" about it while developing a regular Django form-based site (though you'll want to use HTML5 widget types). The only major things that keep coming up as pain points are the inability to properly handle redirects (this is a browser limitation, as JQM can't know that it was redirected on a form post), and the poor handling of "download" links (i.e. download results as CSV or other plain-text form).
The "image inputs turn to non-image buttons" thing also cropped up for PayPal integration, but not a big deal, just create a subclass that uses data-role="none". I'd love to have a less yuck-inducing URL history mechanism, but so far that doesn't seem like it's in the cards (we (using django with global templates) could just use regular urls, but then the page-to-page transitions are lost on "browser back" events... I'm willing to give that up).
Oh, and performance is pretty bad on the iPhone 3G, but then it's pretty old hardware. Oh, and much of the time I wind up reading the source of figure out how things work... but I'm used to that. Anyway, for an alpha, a rather good show.