This is HUGE! BMD has approved an expansion chassis that allows up to four GPUs to be added to a Mac Pro or any manner of PCIe cards. Since Apple won't give us any more than four slots in a single machine, this is a HUGE addition for folks like me who are trying to install Davinci Resolve, ProTools and Final Cut Studio in a single Mac Pro that's also running on a SAN. Too many cards needed to do this in a single Mac Pro, so this expansion chassis could very well be the ticket.
I've got my VAR looking into this rig now and we'll report back if we end up getting it installed.