There are a few Hackintosh design based on PCI-X. THose cards are 64 bits, but can be made to work up to Protools 10 HD IIRC even on 32 bits slots. I have a friend on Madrid that used an HD-2 (Core + 1 FX card) system on a i7 Snow Leopard hackintosh until 4 years ago, but I am not sure if they were PCI or the modern ones.
Those cards can be found on PCI-X (G4 and first G5), PCI-Express (Moderns G5) and the latest