"Sure, you can easily buy a barebones laptop and mod it."
There's a bit of a giveaway in the article linked to. The OS was Vista. That article was written a long while ago. Things have become tighter since then but there are still the sort of options available at vendors such as https://www.pcspecialist.co.uk/
The main difference of desktop vs laptop is that the former has a range of cases to take standard components whilst the latter has to have a good proportion of the components, especially the mother board, designed around the case which itself is styled as much as designed. When you don't have a choice of motherboard there's a limited amount of options available to you.
A laptop case designed to take the latest thin mini-itx boards would be a good start.
Biting the hand that feeds IT
