I think I've said it before, but in this keynote from 1997 Steve Jobs demonstrates OpenStep running on a pair of what appear to be ThinkPad 560s:
Presumably because x86 was the only architecture that could run NeXTSTEP and had portable computers. I had forgotten that NeXTSTEP didn't run on PowerPC; it was x86, NeXT, and SPARC at that point.
Beyond the Sony Vaios one of the only other PC laptops I recall that approached Apple's level of industrial design was the short-lived Compaq TC1000/1100 tablet PC:
It was the only one of the tablet-laptop hybrids that had a removeable keyboard. Unfortunately the TC1000 was hobbled by an odd CPU (the Transmeta Crusoe, which apparently used a VM to emulate x86) that was potentially incredible but just ran very slowly.
And there was the OQO, which was designed by the people who came up with the titanium PowerBook, and had a similar look:
I remember reading that they left Apple because Steve Jobs circa 2001 wasn't interested in making a tablet-laptop. And in retrospect he was right, because none of them were any good, and the OQO went nowhere.
Wasn't there a company circa 2009 or so that converted MacBooks into tablets? You had to buy a MacBook and ship them to this company, and they turned it into a touchscreen tablet.