Agreed. Modeling your own keyboard chassis is possible, and there's plenty of open source models to start from. If you have access to a 3d printer you get down to normal mechanical keyboard price range.

My own attempt is at https://github.com/dancek/dactyl-keyboard/tree/less-aggressi... . While I only have the left half built, I'd say that measuring fingers and tuning an ergonomic layout to your preferences works well. I don't expect to see a production keyboard as ergonomic. Ever.

N.b. the amount of work needed for this build is pretty ridiculous. There's a reason that keyboards are usually flat.