(I'm aware this has been mostly done before, but I don't know of anything that offers this exact combination of features.)
An IRC (and possibly other messaging systems) client separated into a daemon and a set of frontends, supporting multiple servers, and (more importantly) multiple configurable views. Currently I run lots of copies of irssi, each connected to one or two networks, so I'm stuck with the irssi text interface; what I'd like to be able to do is use a graphical interface with a load of predefined views ("UKC", "programming" etc.), and have a text client that I could run from screen that would display the same information. The daemon should also support scripting.