Thrashed out a variation on the initial build...
ModularGrid Rack
Mantis cab, as before. But there have been changes.

Top row now starts with a Doepfer A-119 so that you can inject external audio sources into this thing. Then there's a pair of Klavis's wavetable-based dual VCOs, which now gives you FOUR VCOs. Oh, and they've got internal quantizing. So, four VCOs means four VCAs, and that's what the Codex Modulex Veils clone is for here, but it's followed by a six-input panning module that then sets up your stereo chain, plus it allows you to pan/mix two other signals pre-VCF. As for the VCF...I sorta went all-out here and went with a Rossum Linnaeus, which has some crazy-cool features, including thru-zero modulation. After that, two more Veils-type VCAs from After Later, then Beads for some DSP FSU. The Timizoara is after that, next to the TexMix...which now has the PROPER input group so that you can use the Timizoara AND the Rings as 1-in/2-out FX processors via the Master section. The Stereo input group has no level VCAs, no FX sends, etc...but the Mono input module DOES have those, and you really don't need four stereo mix inputs (the build isn't big/complex enough) anyway.

Bottom row begins with the Tempi/Rene pair. Yeah, pair...because the revised Rene and the Tempi have a lot of "behind the panel" hidden functions that let them do a lot more than either module alone. With that there, there's no need for the Pam's and much of the O&_c's functions are also dealt with (like no need for quantizers with the Twin Waves). The Noise Reap uLoaf is a pair of "misbehaved" LFOs that have a "semi-sync" between them...much more complex than your everyday LFOs. And then, the OTHER "DUSG-alike" besides Maths: the Befaco Rampage. Both owe their lineage to the Serge Dual Universal Slope Gen, but the Befaco has some minor differences as well as 2 hp less space requires. After that, a Frap 321 and another After Later dual VCA give you a "manipulation core" for the modulation signals, and then a VOID Dual ADSR gives you two "proper" envelopes. Rings then closes out the row, placed near the TexMix so that you can use it as something of a "tuned space" for short reverbs...with the warpy capability of modulation over a number of parameters that you tend to NOT associate with short room reverbs.

Yeah, this draws out a lot of downright odd and idiosyncratic things...which really will make this build sound and behave more like an integrated instrument. Now, as for the mults...just use inline widgets, stackcables, etc, as there's not really enough space in the build for mults. You need your space in this purely for functionality. Likewise, some other large modules were booted because...large. For example, the Frap 321 actually has a smallscale matrix mixing capability, but it occupies SIX hp as opposed to the 20 hp of the A-138m. And the Morphagene didn't fit at all, but with the Beads onboard, you won't miss it all that much. But yeah, some stuff got cut altogether, others got smaller, and the overall capability went up. Funny how that works in modular...