I'm a little confused. There was talk of using transistors to drive the anodes, which implies multiplexing the digits is planned. But also multiple Tpic chips, implying no multiplexing. What's the story?
For multiple Tpic chips, clock and latch signals go in parallel from the Arduino to each tpic chip. But the data signal goes from the Arduino to only the first tpic chip. The data output from the first tpic chip goes to the data input of the second tpic chip and so on, in a chain.