Thread: My crookback Eurorack
XAOC makes the Sewastopol II (10hp and 3.4cm) and Ladik makes several I/O modules that are 4hp each. The A525 might work for your purposes (4hp, 3.2cm).
https://www.modulargrid.net/e/ladik-a-525
https://www.modulargrid.net/e/xaoc-devices-sewastopol-ii