I have seen a few in my time but not as many as i’d like to see, You could have one imported but i’m sure the cost of the safe wouldn’t be Your primary concern as shipping it would be prohibitively expensive, By air you would get it quicker but you would spend a fortune on fuel due to the weight, It would be cheaper by sea but it would take longer and the man power could cost you extra.
Just some things to take into consideration when shipping a safe, If You have the money it can be done, Weight, Distance, Transportation method and manpower are issues which can push up the price rapidly.
Why do You think vault doors go for cheap prices 🙂
Why a cannonball safe anyway, Have You always wanted one or are you just concerned about a nitro attack? I would just stick to the standard, It’ll save you quite a lot in the long run.