I'd have to say that you've already managed to paint yourself into a corner. Even if you piled utility module after utility module into that tile row, you'd STILL be screwed. Don't rely on that space to hold ALL of the various utility modules that this build is demanding already...because it can't. Honestly, go back to the 3 row version...you can cram more function into a 3U row than a 1U one. Tiles are really more like "convenience" devices...they're nice, but they're also not a real replacement for fullsized modules, except for basic functions.
Also, modulation sources...well, there's a Maths and a Stages. That's a good START, but if you look at how much modulation the rest of the build really needs to make it do what it can do, you're not even close. Either add more modulation, or back down on the "Sexy" modules.
And one other point: basing the practical operation of your build on a certain aesthetic is, invariably, a huge mistake. The Instruo modules sure do look great, I'll admit...but once you've got the music made with them cut and mixed, no one's going to give a rat's about what your rig looks like. This is leading you down the wrong track, both functionally and fiscally. Instead of going with these expensive-as-hell choices in ALL cases, consider alternatives. You will probably find that you can shave a lot of the costs on this WAY down, and you're also apt to find modules that work as well or BETTER than these spendy things. Put some more time into this, preferably by clearing the decks on this build and starting from the very basics above. Trust me, you'll wind up in a better space than where this is headed right now.