Not out of the box, but the GS Stealth 17" laptops have 3 M.2 slots,2 NVMe and 1 SATA, so one can get up there. The Alienware Area 51M has 2 NVMe M.2 slots and a standard SATA slot.
Ignoring full on desktop replacements like the Area 51M, most 17" laptops are roughly the same size, same for 15" laptops (except the XPS15), and third party cases will either be model specific or ensure the case/bag fits most laptops of the class in the market.
But yes, laptop sizes are classified by their screens. Not their bodies. Hence why the XPS15 and MacBook Pro 15" both have 15" screens but different body dimensions compared to most other 15" laptops.