I've built a few of these modules. They are super-fun builds, and handy functionality. I've used the AND gate and the VCA on several patches to good effect.

Also super helpful when your rack is running low on HP or power...

The "OR" gate saved me the other day; i wanted to patch together to modules at opposite ends of my rack and I didn't have a long enough cable. So I used the OR like a cable extender. Of course, then I decided it would be interesting to plug an LFO into the other input,... :)

Would love to see these listed on Modular Grid! Mystic Circuits is already listed as a vendor, so should be possible.