There are lots of Mutable Instrument clones out there that are a lot smaller in size. Some Mutable Instruments modules are also out of production, so a clone might might be your only option.

What are you doing for a sequencer or even a quantizer? I'm not familiar with Instruo's line so is there one in there? There's a lot of fun to be had by having an onboard sequencer or quantizer around. A micro version of Ornaments & Crime is a great place to start for simple sequences and quantizing. It's 10HP or you can go to Plum Audio and get a 1U version that fits in Intellijel's 1U row.