I got the first test of the circuit going yesterday. I went down to TekVenture to see whether I'm more productive down there away from all of the distractions at home.
Here's the top & bottom of the display circuit's circuit board
The scribbling on the board helped me avoid making mistakes as I was assembling it. It worked because all of the LEDs worked first time. I'm short one 74xx138 so the left four digits don't have any power.
Here's the demo program at work...