Unimog Club UK

 as you say, screen, door tops, roof. also the seats are higher up. no lower lights either. converting them to standard can be expensive, but if you take your time and get the parts slowly you can eventually get the bits cheap. the most expensive things are the screen frame and door tops, as they tend to rot away, you would struggle to make them as well as they have some very intricate folds. also the steering column is different to cope with the raised seats, but i dont know if that would matter if you put it back to standard  and the windscreen glass is special stuff as its very flexible, but again, i dont know if you can change it...