Designing and building this was rather fun. The only real annoying part is getting the springs in place. I printed the image on cardstock, laminated it, glued it to particle board, and then drilled the holes.
For the actual lab, I generally give students the schematics of the gates to see if they can build the circuits themselves. If not, I give them the shortcut guide with the posts to connect. The lab shows how to implement the BUF, AND, OR, NOT, NAND, and NOR gates with both voltage control and with transistors.
As I mentioned, if I were to make another one, I'd add two diodes that would allow NAND gates with only a single transistor. I may also add how to do NOR gates based on a single transistor.
The files section has schematics for the gates. Wiring shortcuts for the Transistor Logic Gates project lab.