Greetings Freaks -
Yes, I know that SPI is "just a shift register". And, for serial in, parallel out, you can use almost everything that is out there.
Not quite as simple for the parallel in, serial out, case, especially since you need the pin that becomes MISO to tri-state when deselected (in order to use several together on the same bus). I've searched a good range of them from several manufacturers, and have yet to hit on one with this feature. It does not have to be a full 8 bits in length for this application, 4 will do.
Oh, I am certain that someone will suggest: just use a tiny. It might come to that, but I'd rather not program yet another micro for an already complex project.