The one thing I don't see is any sort of filter.
-- mog00DFAM, Subharmonicon and Manis have built-in filters, so I think I can work with those before I have a more refined taste on what I want in a filter. And if I get the Bitbox, it has a built-in filter for the samples as well.
-- chlb
Start with a dual filter, then. Something like the Intellijel Morgasmatron, which can work as a stereo VCF but which ALSO can work as two separate VCFs. You can also use this as a "mixer" to go from two sources to a post-filtered "sum" output. This is what I would suggest, as these filters have plenty of different modes as well as separate modulation paths...which, again, you can apply to BOTH filters if desired.