Update old Pro tools system

[nucelar]

Hi, I'm looking to update an old HD3 system and I'm finding out I'm out of options, can you please help to find the optimal solution? I'm doing simple film 5.1 mixing.

I currently have, simplified:
Mac Pro G5 with HD3 system (1 core + 2 accel PCI cards)
192 I/O
XMON
Icon D-Command +expansion

I would like to keep using the trusty 192 I/O and of course the D-Command since they work perfectly fine. My idea was to get a pumped up "cheesegrater" Mac Pro or a Hackintosh but I just found out avid discontinued the HD native PCIe card .

I don't want to invest in an HDX system and I'm very reluctant to go the thunderbolt route that forces me to buy a apple trashcan.
Also the new Pro tools naming scheme confuses me. Do I need Ultimate to mix in 5.1 with the D-command?

Thank you in advance!