A relative of mine claims that she's going to come and see us in 2009 without flying. She's apparently gone quite a long way with the logistics, but it's a
long way. Just look at Google Maps! It'd be the trip of a lifetime though, going by sea or land.
Can't you spend the money on some kind of therapy to help with the fear of flying (hypnotherapy? Didn't BA also used to run a course?). It'd far cheaper, and you'll get to NZ about a hundred times quicker than by sea. and be able to go places on holiday, or even just get around inside NZ.