The Delta VCF from MegaOhm audio looks to be a clone of the filter from a Korg Delta analog synth. I don’t see a way to order on the site so I’m assuming you need to contact him/them for orders.  The modules look like they will fit in a “dotcom” (sythesizers.com) format and/or vintage Moog but the MegaOhn audio site does not explicity state the dimensions.

From their site:
“The Delta VCF is more than just a clone of the filter section from a vintage synth of the same name. All of the supporting circuitry has been changed and additional features were added. It also has a behind the panel normallization scheme which results in extremely powerful and interesting sounds.”