The nano I have mentioned is spec'ed to have 8 in, 4 out. We are hoping to have 4 of the inputs be combined analog and discrete, with configurable comparator thresholds. Ports are still being discussed, but will likely be limited to slave only, but we'll see. It will be an actual Do-more PLC (new DM0 class) in a actual housing, with a target price under $100. It wouldn't be hard at all to take that down further to a 4 in/2 out.
The lowest model of the new platform currently under development will be 6 DI/4 DO, with one model having 1 AI/1 AO. He will cost more, but is a full DM1 CPU. I would like the base model of that under $200, but that is still being determined.
We spent a long time developing Do-more and this is where it finally gets fun. Once you have the technology, adapting it to new stuff like this is easy.