They make m.2 to SATA adapters that have like 10 SATA ports. A laptop motherboard in a case with one of those would be very interesting. I have plans for one but I need to buy some parts (keyboard and laptop fan).

Edit: the adapters run hot and are kind of fragile. I’d recommend having a thermal pad under it thermally coupling it to the motherboard and giving it some support.

Gobolinux?

No one mentioned Bunsenlabs or Crunchbang Linux here, but they aren’t really that obscure.