It seems that the 16" Framework will come with separate keyboard and numpad. The numpad can be placed on either side or taken away, and the keyboard centered. If only they had a touchpad with physical buttons...
I'm sure someone will make a split ortholinear keyboard with a numpad in the middle for the Framework. That'd be the dream.
I can't ever imagine using another trackpad with physical buttons though. Just extend the trackpad over the space that the button would have taken up. I should be able to left/middle/right click anywhere on the trackpad, not move my hand back to the button to click.
