Sometimes I wish that SPI slaves have an address similar to I2C devices. Then I could connect all SPI devices to the same 4 lines: SCK, MOSI, MISO and SS. This would save all but one salve select lines. Pull SS low, send address, the addressed device listens and enables its MISO, the rest as usual. When finished talking to the selected device raise SS.
A long time ago I was talking to a friend about this idea, and if it is possible to put this into a GAL. The answer is yes.