PCI-Express? Why the hell should i need a full computer for that thing to work? Can't they just make stand-alone things? Something you plug, setup some info and start, mine?
You may not need full computer. Just PDU and some simple computer on the chip kind of board like Raspberry Pi or Beagle. In this way, you have flexibility to throw in more cards. This is more for DIY kind of guys. Output will be ugly, no casing, wires everywhere, etc.
I also like to see stand-alone like TM IV. If price is right, GSX I would be a good choice too. At $1600, it's just too expensive. I think $1000 is right price for it considering extra costs for PDU, controller board like Raspberry Pi, USB hub, and some casing.