it should have DIN midi in/outs as well. Pulse sync is cheap with microcontrollers - make sure it has at least 4. Bonus points for USB host.
If it is an opensource hardware, I can help with the code.
This is something I was looking for awhile back, I think I’ve found a solution for my own case but definitely it would be helpful if this existed. This was the closest I found: http://www.bastl-instruments.com/instruments/midi-bastl/
But I think it requires some assembly and also, it uses MIDI so it needs a separate MIDI-USB converter.
Multiple outputs with unique sync multipliers would be fantastic and being able to set sync multiplier would be helpful even if there’s only one output. I tried syncing a bastl kastle, a pocket operator and a volca once. They all naturally/by default use different sync multipliers. I had to borrow a friend’s beatstep to make it work in the end.
Too late now, but i would definately buy one for the right price. A very simple version, just midi in and sync out, but able to handle midi cc´s alo would be awesome.