I've got cx bike(Centurion Cyclocross 4000) which I currently use only for commuting and riding long distances on a road. Is it possible to use some longreach caliper brakes on it (e.g. Shimano BR-650 or Tektro R538)?
I've just looked at the Centurion website and it's not clear from the pics or the German specs whether the frame and forks have caliper mounting holes. Look for a hole in the centre of the fork to take the caliper, and a corresponding one in the centre of the rear cross-brace above the wheel.
If those are there you can use caliper brakes of some kind, if you can get ones with the appropriate reach.
Bear in mind that you may also need to change the levers to pull a different amount of cable, or use some kind of adapter.