What does this have to do with the hint? On 31 July 2006, New Zealand will begin the change to new coins. The new coins are smaller and lighter than the current coins. The current 50 cent piece is one of the largest and heaviest coins in circulation today. Last year, the Royal Canadian Mint was selected to mint New Zealand's new coins.
This question was perhaps a bit too obscure and nobody managed to come up with the correct answer (or indeed, any answers at all). However, thanks to Amy for the idea for the question!