@aral Pitop used to make something like you describe but it appears they no longer sell it. There are of course various "Pi laptop" kits and projects you can find on thingiverse and printables as well.
If it isn't critical that the SBC be embedded, there is always the option of a "lapdock" (like Nexdock and friends) with the SBC mounted in a case somewhere on the outside.
@kyle Thanks, Kyle. I did order one (CrowPi L) for the Pi 4 I had gathering dust but, yeah, looking for a generic solution because I don’t want to advertise Raspberry Pi after they proudly hired and bragged about their spycop.
A screen/keyboard combo with external outputs does sound like the most practical/realistic option right now :)