This is my plan for an initial build around the Neutron. My budget is ~$3000 and my goal is something that allows for a lot of sound design for sampling while being immediately performable and at the same time having the possibility of, though not specializing in, generative stuff.
The Neutron was really good at sound design and generative all alone and I learned a lot using it (I even got pseudo-euclidean rhythms by putting the 2 oscs in lfo mode, turning on sync, and playing with the delay!). For now I just want to cover its missing aspects and expand it. The intellijel 7u cases are carry-on compatible and I will be traveling in the near future so that's why I'm choosing that case. I have already owned the neutron for about a year, and aside from traveling it will not be racked, giving me some room to grow. I always run out of attenuators, vcas, and envelopes while patching the neutron, so that's why those modules are there. Also a sequencer capable of transforming one instrument into a completely different one over the course of a performance, and that can also handle triplets, record cv, and do a bit of sampling is why I chose the nerdseq over the hermod and metron. Initially I was gonna give the nerdseq mutes with an addac latch module, but I learned a launchpad gives it that functionality as well as x0x and clip-firing style flexibility so I nixed that module, at least for now even though it would still be useful for other things like hocketting. It will connect to the disting ex via i2c (when that expander is soon released), which gives multi-velocity, note, and round robin autosampling and polyphonic sample playback, which is really awesome and will make a great seq/samp duo, as well as a looper and other utilities for experimentation. The disting midi breakout is there as a price/hp placeholder for the nerdseq i2c breakout module. The 2xMIXIV modules replace the ATN8 I think for the better. I found them because the atn8 is not available right now and I'm thinking of purchasing soon. The faders are probably a bit more usable than the trim pots on the ATN8, and it ends up consuming the same hp. I have lots of attenuator/mixer/vcas because setting up, for example, a reverb that ducks the attack of a lead patch takes 3 vcas alone. Assuming 3 voices and a sampled bass that I want auto-ducked, that's another 3 vcas plus 3 attenuators for separate duck levels of each of those 3 voices. That's 6 vcas. Etc. So lots of vcas. Also I have at least 5 stackable cables already.
I want the ability to make an actual 'track', as well as the ability to set up self playing patches. I've gotten some really cool stuff regarding the latter out of the Neutron alone, but when it comes to an actual track the amount of computer involved in sampling and performing really kills the workflow. I like the Seq24 line of sequencers but they are kind of unstable, and this build addresses those issues.
The (not)'full' build plan is here: 
Eventually working towards tzfm and quad(oct)rature play (formants, morphing, more performability) from modules included here (ignore the hermod and bitbox. That functionality is replaced by the nerdseq and disting): 
If I find out the new Nerdseq P will be given a CV input expander then I'll save the rackspace and go that route instead, but otherwise I'm eyeing a b-stock demo nerdseq for a purchase soon.
Thanks in advance for all advice!