Not quite the start of IBM's laptops
Predating the Thinkpad line a bit, IBM also had the venerable L40SX, my first laptop computer. Beige, not black, with a 640x480 grayscale LCD, a 60MB hard drive and a 20MHz 386SX processor. I don't recall how much RAM I had in mine, it certainly wasn't a lot - 2-4M perhaps? It was a workhorse, though - I ran Win 3.1 and OS2 on it and used it extensively for working from home and on the road.
IBM also had the "portable" PC (standard XT packaged in a sewing-machine sized case with a small amber monitor, similar to the old Osborne systems) and before that the venerable and similarly-packaged 5100 (data tapes and build-in BASIC and APL, oooh!)