Carriages with compartments are one of the reasons I prefer travelling by train over other forms of transportation - they're basically an implementation of the travelling room concept, albeit non-private. You usually have to share the compartment with up to 5 other travellers, but a handful of people in a small room tend to be much quieter (and more friendly) than dozens in an open plan carriage. Sadly, compartments are increasingly rare nowadays, even in first class. I assume they're less space efficient in terms of passengers/m².

Of course, if you can afford it, you can get one like this... http://en.wikipedia.org/wiki/British_Royal_Train

My grandparents used to call their RV 'the wheelhouse', which I guess is like the more common term 'motorhome'.

When someone else is driving, for you it certainly functions like a room that goes places.

I mean, isn't this a room that goes places? http://www.prevostcar.com/DB/markets/market_motorhome_4high....

Major changes would have to made to cars so they could function like that for everyone safely, though. Even with robot drivers, I still wouldn't trust that I could be walking around cooking and playing ping pong while we're moving.