The Cherry MX-ULP discussed here (here is the datasheet) appears to be a similar thing, but using metal stamped parts which are less bulky than plastic. It is thus shown as 3.5mm deep, albeit this seems to be due to omission of mounting pins (I guess this switch is surface mount). Current Framework key travel is quoted as 0.5mm whereas Cherry claim 0.8mm for their design (that’s >50% more).
The linked discussion suggests the Cherry MX-ULP fit the framework in terms of height. Not only might this be an interesting option for building an Atreus keyboard, this limited application could perhaps also be an opportunity to evaluate their wider adoption in Framework laptops .