GarfieldModular - Thanks for the reply. Here's the image as a link (i hope).
I already have the modules shown. I make my own cases so the cost is limited to hardware and PSU. My next case will definitely have a 1U row.
I agree 100% with your ADSR comment. I actually forgot that was one of the next modules I intended to buy. Do you think something like the MI Stages could serve as an envelope generator while taking over some sequencing if I omit the Metropolis? The Metropolis is huge but I felt it would increase the "playability" of the rack. There's plenty of smaller sequencers, though.
I thought a third filter would be too much for two rows. Glad to be wrong. The Jove System 80 filter sounds great...or maybe a ladder filter.
Any recommendations on "must have" envelope generators (besides Maths) or filters I could check out?