Hey Duncan, while you're here...I actually have a similar request (e-mailed Erik a while back).
Could you possibly tie my username to a different Live account? Before, signing into C9 didn't translate into an actual signin of the Live account; thus, the actual Live account I use for all other services would still stay signed in. Now, signing into C9 means I have to sign out of every other service that I signed in with my other Live account, which is kind of inconvenient.