I remember seeing the name of such a company on the credits page of the Playdate [0]:

https://metric-designworks.com/

Looks like a very humble site/company, but then you see that they have Teenage Engineering as one of their clients, in addition to Microsoft, etc.

When I have dreams of having a cool successful kickstarter around some quirky hardware musical instrument I’d invent, I definitely see myself reaching out to a company like that..!

[0] https://play.date/credits/