I'm using a nifty Focusrite box right now, but I'm on the long term prowl..
Purple has a stereo-only box in-progress: http://www.purpleaudio.com/Product/master.html
I might end up with a custom Crookwood mastering console.
and I can only guess that the eee-vil Mr. Blackwood is taunting us with more Crane Song insider bird-chirping.
... Might be worth waiting for.