As with Wayne, I have a 2012 Wi-Fi-only Nexus 7 ($200 a year ago) and an external keyboard/case which was $30 delivered on ebay. It's running stock lollipop which is buggy on this particular hardware (no probs on my nexus 4, except the freakin' battery life which is terrible).
http://i.imgur.com/jEXA480.jpgThe case just has a groove which the tablet fits into in landscape orientation, and plastic clasps when acting as a case which feels very sturdy. It works out fine on public transport in my lap, and very easy to switch between use as a tablet and a tiny laptop. But, the keyboard is tiny even for my small hands, and no tilda key :( . I have used it effectively with lecture chair tables to take notes using a markdown app. I would say this type of solution would work out fine for an 8-10 inch tablet with more surface for the keyboard, as long as it has all the keys. Connection is via bluetooth. That would leave finding something with 4G and stock android, which probably narrows down the field quite a bit. The nexus 9 fits that criteria but it's fairly expensive and I hear the build quality is not as good as it should be for the price (a little give in the curved case, screen is slightly cheapish etc.).
As for a 'true' linux tablet, that's something of a white whale :/
- Edward
