Re: At Pen-y-gors, re: they know who you are...
Yes you could do all that but you'd be the proud owner of something that was unmistakably stolen. These city bikes are so obviously city bikes that even if you resprayed the thing everyone would know. I doubt you'd last long before a cop or someone decided to have a closer look. And probably the parts are deliberately proprietary to prevent them being cannibalized.
Scooters are a different story. First off they can phone home so good luck with that. And even if you take out the gps & mainboard you need to replace it with something that works instead. And a charger. And the simple countermeasure to people doing that is to pour epoxy resin around all the internals - battery, mainboard, electronics, screws etc. so that the effort required to "hack" the thing becomes excessive.