I though a good little board for testing out the shift register multiplexed display would be to make a little board using some Ebay special common anode 7 Segment displays. I've got that board on order over at OSHPark.

https://oshpark.com/shared_projects/YzQBaEu3

Here are the small displays next to a larger 3-1/2 inch digit I also got off of EBay.

Thinking about it more, while I'll complete the mutliplexed display test, when building larger displays, it may be more troublesome to run the 8 power wires to each digit, then it would be to run 2 power wires and 3 signal wires with some local circuitry to drive each digit. I'm thinking possibly a BCD decoder and a shift register to power each digit, feeding the serial out to the next digit. In that way the display could be refreshed by sending 72 bits, rather than constantly having to drive the multiplexed display.