The instruments that you can see on this website and in the videos are currently the only versions that exist. They are not for sale.
I am currently developing plans to make a small batch of the instruments for sale in the near future. Please let me know if you would be interested in this, as it will help me approach it in the best way. Send me an email or say hello on Twitter.
A physical copy of the Book of Knowledge of Impractical Musical Devices will be able to purchase soon. Sign up to the mailing list to find out when they are available.