I put together an address and data bus display for trouble shooting an apple 1. Attached is the schematic.
The TIL311 hex displays are available on Ebay for now at various prices.
One can also find the 22 position card edge connectors on Ebay.
See the attached photos and schematic.
I used a 5V wall wart supply rather than using the 5V bus power. Be sure to attach the wall wart ground to the bus ground pins 20 and X.
Post back if you build one. Let us all know how it turns out.