I prefer the idea of the stick computer cause it would fit under the space behind N900s screen when keyboard opened. Was thinking of making a casing where you can stick N900 in the case and to the usb and have a proper specs computer in your hands. The intell sticks have their own micro usb power port so my idea could work: to have intel stick behind N900 screen and beside it a slim external battery giving power for the stick computer. So it would be a dock where you stick your N900 when you need to have up to date machine with horsepower (as for some would may like to use it for running kali). They have in them as default the win 10 and you can get nethunter from windows store. Ubuntu can be set on it so it can probably run most of the needed tools on linux side. It has usb2 and usb3 depending on the model, 2gb ram and 32gb for storage plus micro sdcard slot. Just a bit pricy to buy if it is unsure how well it would work. But it would be easy to build casing for the stick and extra battery for them to serve as a dock.

But as I mentioned before I think I will first get to know this N810 I have.