I welcome this new mailclient. Unfortunately it currently leans differently from what I prefer, but perhaps it is close enough that the source code will form a useful basis for what I prefer (no html (and a decent html>text renderer for the brain dead services that don't provide (useful) text parts), no rich editing, threaded -- not gmail style conversations).

At any rate it seems like a more viable (for me option) than eg hacking on prayer (because, I think it's just silly to try and work with something exposed to so much bad user input/data as email -- in C):

http://www-uxsup.csx.cam.ac.uk/~dpc22/prayer/