Heh, you could put something very capable and integrated really quickly using Emacs--all the building blocks are already there. I imagine combining Org-mode, an email client, your development environment and whatever else you happen to use in Emacs with a bit of elisp glue would do most of what the post proposes quickly and elegantly.

Coincidentally, can you use AucTeX's LaTeX previews in other buffers? Being able to see LaTeX equations in emails and chat buffers would be great.