Thanks for showing your interest, also to @colpitts, who I’ve had an email converation with earlier.
For now my focus is on the Striso board, but I have a couple of half finished Striso boxes lying around that I’d love to finish. Its focus is more a standalone instrument than a midi controller and since it is based on older hardware it is not compatible with the firmware updates for the Striso board.
I’m not sure about the price, it’s worth more to see them being used 
Between 1200 and 1500 euro/dollar I’d say. Depends also a bit on how well they will work when finished and how much effort goes into that.
The left hand side is quite special, featuring an auditory illusion called perceived pitch height, making it possible to shift octaves in a stepless way. This way only one octave of keys is needed while still being able to play multiple octaves. More details on the left side are in the 2014 NIME paper, paragraph 5. The left side keys on the prototypes are less developed than the right hand keys, being a bit less sensitive and on the small side. I’d like to have them bigger to have better control.
It has an internal speaker and rechargeable battery, and micro USB for charging (that might be worthwile to change to USB-C though).
In the future I’d love to develop a new version of the Striso box but that future is very unsure. The design is really playable, and quite well resembles the way of playing my modified accordion, though the dynamics are obviously different.
Another path I’m taking is the Striso duet, two Striso boards mounted on a frame to make a similar instrument as the Striso box but with the same keyboard left and right. There are some videos in the topic Striso duet experience if you’re interested.