Bud, why do you even have to look?

Framework.

They sell the mobos as is and they even sell cases to put them in. Go to their site and have a browse 👍.

For your original question: I would not bother with a CPU with less than 6 physical cores. 4 laptop cores might work, but you can’t upgrade them.

Laptops have some advantages and if you already have one it is a valid alternative, but I would not bother buying a new laptop.

Advantages are built in battery as UPS, keyboard and display, but upgrading is very limited. If it has an additional dedicated GPU you might even forward that to a VM.

32GB ram should work, but with 64GB you will have more possibilities. Some laptops are limited in functionality, but new ones should have the necessary virtualization options. With 6+ physical cores modern laptops have some great virtualization potential, but with modern big/little core Intel CPUs virtualization might need some additional tweaking.

Cooling wise it might be worth looking for a model that doesn’t push air out in front of the opened display. If you store it closed the limited cooling can cost performance.

Thunderbolt is a good but expensive way to add new hardware like 10G networking or fast external storage.

Personally I extended my lab with an old Dell Precision 7540 workstation laptop, which is really great but not cheap.

Financially, it’s going to be a giant waste of money. There are laptops with desktop processors, but they are all either gaming rigs or professional workstations, meaning, they have very muscular graphics, for which you will need to pay, but will have no use (unless you’re into protein folding or finite element calculations). Also, everyone who makes this kind of hardware sells it with Windows pre-installed, for which you will also need to pay.

Worth it, low cost low power built in ups. Add cooling, Watch the batteries, might go bad swell etc. add external storage