About the name "ThinkPad"
Until 1992 IBM used to refer to their products only by numbers. This was true also for the notebooks manufactured until then and the tradition of those numbers has survived in the form of the type-and-model numbers with which every specific IBM product is still referenced much more precisely than by its common name.
Rumor has it that IBM first intended to give the designation "ThinkPad" to their pen based computer 2521, which became the IBM ThinkPad 700T. But then they decided to extend the use of the name to their notebook computers and hence the first ThinkPads hitting the market in 1992 were the ThinkPad 300, ThinkPad 700, ThinkPad 700C and the mentioned TabletPC ThinkPad 700T.
The ThinkPad name itself was inspired by leather-bound pocket notepads issued to all IBM employees with the corporate motto 'Think' embossed on the cover. The combination of Think and NotePad lead to the name ThinkPad. IBM's corporate naming team was initially against using the ThinkPad name since all previous IBM computers were referred to by model numbers rather than names. However, the popularity of the ThinkPad brand with the press convinced IBM to retain the name.