| br>fwiw, there's a bunch of CV to OSC (and vv) modules that should mostly get you there (there's probably more, idk):
none of them as far as i can tell use a rpi, if that's a given (there's so much IoT stuff ... *), but both "motivation radio" and the rebeltech one are open source. the former actually uses a MCP320x ADC, so that's probably the more relevant in terms of hardware / input circuitry **, you'd just have to scale up to 16 inputs + add a few things, depending on what "a way to take in both bipolar and unipolar cv" implies, exactly (ie is there a toggle switch to switch the range? or would you want to set the input range in software? or perhaps "bipolar" is ok for both purposes?).
IIRC the "OpenSoundModule" runs a little webserver thing for configuration purposes, Aithēr also comes with an app. a dedicated 7" touch screen just for configuring some OSC messages almost sounds like wasted effort (to me); at any rate it could always be added later.
another idea (if "scaling" included attenuators / so you can leverage the panel / case design) would be to start with an existing and suitable-looking thing such as https://github.com/16n-faderbank/16n, throw out everything you don't need (DAC/CV out), and replace with what you need (ADC/CV in) + add a cheapo wifi module such as this one (or use a wifi-capable thing in the first place (not a teensy), e.g. the espressif or particle stuff used by above modules)
also fwiw, there's a fairly simplistic OSC client in the "terminal tedium" repository (here). it simply polls the MCP3208 and sends the data out via OSC.
the choice of which i suppose somewhat depends on your detailed requirements (e.g. sample rate, how much clock jitter can you stomach, ...); for the purposes of converting to OSC, this sort of considerations probably don't matter much though. (same goes for the ADC chip)
if "standalone" = doesn't have a -12V (or -15V) rail, this kind of MCP600x based input circuitry needs to be biased differently, see e.g. here (figure 4). br> br>