I am still sad that things in the form factor of the Oqo never caught on:

https://en.wikipedia.org/wiki/OQO

With a modern multitouch screen and a slide-out keyboard it could be both a capable tablet, and do a lot more... The surface book is too large.

edit: this thing too, the whole 2007 era "UMPC" fad:

https://en.wikipedia.org/wiki/Samsung_Q1

imagine the same form factor but with modern processor/screen/battery tech, 802.11ac dual band wave2 wifi, a few USB type C ports on it.