We have legacy specialised (read expensive) PCI hardware in separate boxes and are looking for a motherboard solution that would enable us to put them in the same box(synchronisation and control reasons) .
Each card, when flooded, will require upwards of 90% of the PCI bandwidth. Therefore, we are looking for a solution which has multiple buses.
Using PCIe instead isn't really helpful as we are dealing with legacy hardware..
The PCI bus connects to the Southbridge in old motherboards, MCH I think they call it now. I don't know of any boards that have two of these. I think the question now is which is the better idea/costs less. Keep the boxes separate, or buy new expensive machines.