Although I don't know how HMV determine the selling price of imported items, I suspect the costs per unit is significantly higher than it would be if the customer ordered it direct from an online store. For one thing, there is a second retailer in the chain. Also, HMV have reps around the world who buy stock to export to other countries. Those reps have to be paid, all of which has to be reflected in the ultimate price to the customer.
I wonder, then, if it would be useful for me to order a few extra copies from cdjapan to sell here online.
I am not sure of the legailies of (re)selling items online. It certainly is not something we could do on this forum without violating ProBoards ToS. Also, I don't see it as a practical way of enabling members to obtain these items because, if they could order them from you, they could presumably order them from CD Japan.
If you are suggesting ordering a small number to sell on to your personal contacts, friends, relatives, acquaintances, etc, that is entirely up to you. Bear in mind though that, if you order more than one at a time, you are likely to incur import duty which would almost certainly defeat the point.