I think I decided that the easiest and simplest solution to the chip select problem is to use a small PIC processor to receive a serial data block with the address that the master processor wants to talk to. If the PIC sees that that address matches its own (defined by DIP switches) it will enable the CS.
Why a PIC? I love the MSP430, but being a 3.3V part, I did not want to mix voltages with the ADE7763 that runs on 5. PICs are cheap and ubiquitous with lots of free support at tools. I also happen to have a PIC programmer (EPIC) I purchased way back in 1999. So now I take a break and start writing the code for the PIC.