If I don't need to have a screen on the thing, why be constrained to use the laptop form factor at all? That is, in significant part, a product of needing to stick the monitor where it is.
The best way to type is still with a keyboard. It's useful to have touchpad for backward compatibility. You need battery, a box to put hardware in and a keyboard, basically that's a half laptop
Sure. I don't need to have the bulk of the electronics in a flat package beneath my keyboard, though. At that point, I can use higher-profile form factors.
Sure, but does the touchpad have to be below the keys? It makes sense for a laptop since it matches the dimensions of the screen when folded closed. No screen means it can be rethought.
Where would you put it? If you type with both hands that's the most convenient. I've only seen side touchpads on small 6-7" laptops where there is no space there, and you can't type with both hands due to their size. GPD has some models like that, e.g. GPD MicroPC:
We're already using cables to interconnect the peripherals to the main computer. That's the whole gimmick of the glasses. Why not have a keyboard on top of the computer, laptop style, with a wired USB module with the IO ports and a trackpad on top? You could recess the port on both ends so the base is flush with the body of either module, so it looks like a permanent part of the PC but is still removable for replacement and transportation.
I've seen people's wrists accidentally touch the touchpad while typing and completely screw up what they were doing. It's happened to me personally as well.
I don't know if there's a better placement, but it's worth considering. I have seen Bluetooth keyboard/touchpad combos that have the touchpad to the right of the keys, but no personal experience with them.