Why not use Hipchat through XMPP?

Since we mostly use OSX, we configured Adium with an inline image plugin : http://www.adiumxtras.com/index.php?a=xtras&xtra_id=7926

We also use a group chat theme that replicate hipchat look and also support "system message" formatting : https://github.com/davidpaquet/hipchat-adium-message-style (I forked it to add "Bitbucket" and "Trello" as system messages senders but the real work is from Seth Chisamore).

I'm pretty sure you could achieve somethign like this with Pidgin.