I chatted with a couple of the kiwi riders (Doug and Ed) during pbp (me being an ex-pat kiwi as it were), nice blokes and I enjoyed their company.
I must admit to thinking about this ride. It's been a while since I was in NZ and, to my shame, I have never really seen the South Island. I think I'd ride supported if poss, hiring a campervan that my wife would drive. Just got to price it all up and have a think.