A Logitech K400 Plus keyboard with integrated touchpad instead of a numeric keypad:
Mainly, I'm interested to see if I can speed up zooming/panning in Inkscape, Gimp, EasyEDA, KiCad, by using my own Linux userspace daemon that grabs the touchpad, and produces customized events and controls instead of mouse movement when in "tool mode". I use a mouse to control the pointer, but my working style in these is such that I zoom and pan very often, and I'd rather use my left hand to do that (separately from my mouse control).
Alas, I'm right-handed, and keep my mouse on the right side of the keyboard, so the touch pad is really on the wrong side for me. But the fact that this keyboard is narrower than full-sized keyboards, helps.
If it does not work out, I can always donate it to a family member who has a media center but no wireless keyboard for it.
(This was inspired by Simon's
Programmable keyboard topic, although my use case is obviously different. I initially described the idea
in this post.)