Does that mean that you could get a passenger side cubby door from Nissan and fit it to the driver's side on cars (like mine) that don't have a sub, thus creating another accessible storage space?
Correct, I have done it myself
Great - any idea how much it costs?
Not sure in all honesty. I picked up mine as an eBay bargain! Might be worth speaking to the chap who is breaking the Z in Ireland as he might be able to help out