Hey guys
I have been doing some digging and I think I have found where to buy the part from:
Nissan Japan - Rear Backup Camera Kit (Japanese Spec)
Would work out cheaper to import the part yourself and get someone to fit it than to get them to supply the part as well.
The quote I got was $1100 for supply and fit from GCCS.
You can buy the part for $US595 = AUD $708.. so might save you $250 or so...