As far as products go, check out the archive for information about the Ambika. It is a 6-voice hybrid poly (somewhat similar in architecture to something like the Novation Peak), based on the Shruthi. While discontinued, you see them pop up used every once in a while and people in the community have taken the open source schematics and produced PCBs for building yourself.
Plaits has not been open-sourced yet. If/when it is, the DSP will probably be ported to a bunch of platforms (for example, there are externals that run Braids in Puredata, VCV rack, Max for live patches and a bunch of other things), so if you have a capable enough computer, you could for example, create a virtual VCV rack with 8 Plaits in it (you could do this with Braids now–it is the “Audible Instruments Macro-oscillator” in VCV).
The interface of Plaits is pretty tuned to being used in a modular-environment (used in accordance with other modulation sources and audio modifying modules), and while I think it’d be cool to explore some of the modes in a Poly or in a multi-part, parameter-locked-in-sequence context (in fact, I have 2 Plaits in my rack and that is a ton of fun!), I think it would get very complicated quick (in terms of both interface and things you’d need to include to get the most out of the various modes, as well as a project).