Of the modules mentioned, I have A-145-4, Quad VCA, 3xMIA, Pam's, and the Out v3, and like them all. One nice feature of the Out is the cue input, which lets you audition sounds being constructed without repatching. I also have 3xVCA, and should have considered Veils as a Quad VCA alternative. As a Maths alternative, I was considering the Cosmotronic Delta-V (which is small) before I went with Falistri. I really like Falistri, but I wanted more than two envelopes, and to be able to use it as one or two oscillators. So I added Quadrax, which is packed with functionality. You are tight on space, so some careful planning is needed, and then availability will be an issue...
-- plragde
Thanks plragde. The space is indeed tight, but at present my thinking is to make it compact, but with interesting functionality, and keeping the price a little under control too.
In the meanwhile, I've started sketching another rack with some of these suggestions in it. I'm looking at the Falistri at present, which looks interesting - when I get a chance to see how it works.