I have one for sale, along with a fifty/fifty power amp.
I mostly post over on the gear page. Here's a link to the sale ad: http://www.thegearpage.net/board/index.php?threads/mesa-boogie-studio-preamp-fifty-fifty-power-amp.1666808/
It's also on reverb.com here: https://reverb.com/item/1626491-mesa-boogie-studio-preamp-and-fifty-fifty-power-amp
Price is pretty negotiable. PM me here or at TGP or Reverb.com if you're still looking and interested in the one I have
thanks