Conventional magnetic fields are observed to be loops. Where a magnetic field exists, it is impossible to carve out a volume of space such that more magnetic lines enter that region, than leave. Although a bar magnet has identifiable north and south poles, the imaginary lines of the field actually continue inside the magnet, forming complete circuits.
If you had a sphere which was all north all over, there would be no way for the lines emanating from that pole to meet with the interior south pole. That sphere would effectively be a magnetic monopole, as far as what we can tell from its exterior. If we contain that sphere in a region of space, that region of space has magnetic field lines emanating all over, without any such lines re-entering it.
If the search for magnetic monopoles ever turns up something, then it will confirm that such a sphere can exist.
Now of course could have a sphere such that most of its surface is a magnetic pole, like north, but such that it has some small region (or regions) where the magnetic lines emanating from this north re-enter into the sphere. These regions would then be de-facto south poles, though, making this different from a sphere which is north all over. If you make an object by tiling a sphere with magnets, I suspect you will get this kind of animal. The inner field lines will "escape" somewhere.