Or you could queue up and get one of Uli's ARP 2600 clones.
Sure that the ARP 2600 is a sexy synth. Do you refer to use it as a standalone synth or to interacting with your modular system?
-- baygiooday
Yes, and yes. The B.2600 is part of a larger "environment" in my studio for all of the modular and patchable gear, located especially so that it has ample access to the Digisound 80. I've used that 2600 + Digisound combination for literally decades, and given that Uli's version works just like an original "rev.4" (when new! one that's been sitting around since 1978 won't sound like a new one), the "fit" should be fine. I already know that the patching spec is identical to typical Eurorack norms (just like the original), so no concerns there.
As for the BSP, I have two, along with a basic Keystep and a Keystep Pro. Given that we're talking synth controller here, I've found that the KSP is super-useful with modular setups, since you have a manual keyboard, the usual mod controls (ribbons), but the clocking and multiple lanes of sequencing is stepped-up from prior efforts. More elaborate, more powerful. But the pair of BSPs also has some perks...such as being able to set up four different but harmonically-related MIDI structures that loop but never re-match, then merging that down and sending it to a single synth as an evolving backdrop across all four lanes sent by the pair.
However, I would still strongly suggest having a MIDI interface here. Even if you don't want to send MIDI note messages, you're still going to want to lock up the sequencing to the DAW's clock, and you'll need a basic interface to do that. Fact is, though, just get a proper one that can handle two voices or more...because you'll eventually want that AND then to be able to use other time-locked controllers along with it.