I've seen them here in Finland, but new bikes seem to come with Schrader or Presta valves. Don't know if spare tubes with Dunlop valves are still easily available here.

I seem to remember from my childhood that a Dunlop valve is a completely separate design from the tube, held on place with one lockring. In fact I used to carry spare valves with me as a kid, as it was a fairly common prank among us to "borrow" valves from a friend's bike, rendering the tyre impossible to inflate.

--J