This cropped up in discussion elsewhere on Element 14 and may be worth considering for a future show.
https://www.element14.com/community/docs/DOC-83675#comment-96896
Heathkit in the 1980's produced and sold an educational/personal robot in kit form or pre-assembled called the 'Hero 1' and then later the 'Hero 1 Jr.' and the 'Hero 2000' models.
https://en.wikipedia.org/wiki/HERO_(robot)
They were much sought after by young technical enthusiasts at the time, but the pricing probably placed them more in the college/university domain.
If one can be obtained (around 20,000 were sold according to Wikipedia) then it may make an interesting teardown project for the show. If not, then perhaps building a modern equivalent would be an alternative idea for the show.