I remember "luggable" as the adjective of choice for such machines through the late 80's and early 90's. The PC Magazine columnists (Dvorak and Seymour and others) were fond of it.
I remember "luggable". There was an April fool's section in BYTE in the late 80's advertising a line of hand luggage made to look like portable computers. The text said something about the size being painfully realistic and not fitting under an airplane seat.