Here is the link to a thread on this topic from a while back. It seems that MacResQ no longer has them in stock, but a few other suggestions were made as to how you can get your hands on one of these. Also, try calling macresQ anyways and see if they have a couple laying around that they haven't listed yet

http://www.macmod.com/component/option,com_simpleboard/Itemid,/func,view/catid,21/id,1349/#1349