>What I definetly DONT want is a smartphone or any other >NSA/CIA/MOSSAD/KGB/whetever-sponsored tracking device...
Because of this point alone no currently on-market cellular device will fulfill your needs. Incl. chromebooks or tablets with cellular capability. Barring a small laptop the best you could do would probably be a mini-ITX board in a custom enclosure, but that's fairly large for the intended purpose.
