Turned out that chat support was pretty straightforward to add, so I went ahead and finished the patch. Should have pretty much everything now, besides buddy icons, but note that the chat support is not extensively tested yet since I don't use that feature. I noticed that the pidgin-libnotify task is assigned, apologies if someone else is already working on this.
I also pushed the package to ppa:jconti/gnome3 for further testing. IM support should be pretty solid, I have been using it for a while now. Please let me know if anyone has any issues.
Oh, status support also requires a patch to the pidgin.desktop file that adds X-MessagingMenu-UsesChatSection=true.