Moogerfoogers, Koma, Lightning Wave, etc are out there with CV options.
You could get a nice fraq diy setup from paia for under $600. Pretty flexible setup too.
Sequencers: future retro zillion is something like the turing machine in inspiration and function (just random versus scales).
Frequency generators (test equipment) can be had cheap...just attenuate.
Sq-1 as a modulator or sequencer. I also prefer keystep to beatstep, but both could work together (one almost like an lfo, or set voltage thing)
Passive ring mod also helps make new out of old mod sources.
Also, there are a ton of cheap modular synth boards out there....just get a cheap power supply and case them in whatever you want. I ran two 9v batteries and have a LPG in my guitar setup.
Also, some eurorack modules run at 5vdc...so that is easy to adapt to a new case, esp if a diy board.




