It's the only reason holding me from getting a Deneb. Though I think that if such an amount of logic is derived from Buster to Deneb maybe you could use that in some kind of multiple DMA enabled ZIII/PCI bridge. It would be the only one in the market (Mediator in NOT true DMA).
Or better, replace Buster with fpga like the Indivision does for Denise but with cables to a PCI solution. Fast PCI + ZIII would be sweet.