Yup
@FridayJones nailed it about the wonders of decomp. While it lacks in the traditional sense of dignity. It really is quite remarkable how much life is created by one of us silly humans dropping dead.
I have no idea how donation works in New Zealand. Though it may be possible to add a stipulation as part of your living will. That they may only use viable organs for transplant, while leaving the rest of you alone.
I have not the first clue how one goes about arranging this but. If you really want to leave a pretty corpse. (I never thought I would ever use that sentence, ever.) You could be mummified in a similar fashion to Lenin, Chairman Mao and I think there is someone else as well, but it is escaping me right now.
Simply put they have been "pickled" not with vinegar mind you, but using formaldehyde and a few other chemicals. Once a year or so, they soak you in a lovely bath of preservatives that keeps your body "fresh" then a little makeup, new clothes and hairstyle. Then put you in a vacuum sterilised glass casket for people to see you in.
Again, no idea how to have that done, or how much that would cost. (Probably a hell of alot).
For me personally, I couldn't care less. Catholic service, cremation, mummification, immolation, wrapped in a shroud then stuffed into a cave, floated down the Ganges, slapped naked then dumped in the East river, ejected into space, stuffed with as much TNT as me arse will hold then blown to bits.... Ok enough. You get the idea. Lol.