I wish. Yes sometimes it makes you want to invent your own products. A very determined person might be able to manage this, depending on what it is. It would take a lot of work, business plans and marketing to get a cage produced and on the market and might not be very profitable due to competition, although someone has done this with a wood cage range, so a cottage industry could be possible, but would probably be a sideline and costings would need to be done carefully.
https://www.etsy.com/uk/listing/2535...?ref=related-3
They do a 90cm version as well. I very nearly got one but stuck to a traditional cage as it was an upgrade and Charlie was used to a cage so wanted something similar and to keep the layout similar.
A few people have made and sold hamster accessories. And the piggy room makes houses.
Making a wheel sounds great!