Thread: What is missing?
Cool rack so far. I agree with Exper, but I think Hot Glue and Quad Sputnik are overkill in terms of HP. What do you think about something more minimal, like this? It is a 4 in 1 out mixer in 3 HP that can mix CV as well, and is relatively cheap. Malekko also makes a 3HP mute module which could synergize with your Rosie.
For a basic VCA, I think you could do worse than this.
Sputnik also makes a compact multi VCA/Mixer.
The Optomix is hard to beat for a starter low pass gate, revision 2 is coming out (soon?) and will have even more function.