Letting go of my x0xi0 since it is just not getting much use right now. This was built by Brian Castro himself in late 2011. This was from a small run of prebuilt ones that he did which I was lucky enough to get from him.
It is the Rev B and in the custom aluminum enclosure. It will come in the original box with power supply. It is in excellent condition. It has never left my house/bedroom studio (n/smoking, n/pets).
Info on it can be seen here : http://www.alphazone1.com/x0xi0/synth/
$1250 including shipping to the lower 48 US, buyer to take care of any PayPal fees. You can still buy this complete kit for $975, this one comes assembled directly from Brian himself.
I have sold both software and physical items on KVR under the same username fragmentated where there is feedback in their marketplace feedback thread.