You'll have to buy it online, unless you manage to get a japanese copy.
I see your poinbt, why get another re4 for another system if you already have it for one system?No... Not worth wasting my money. Though I like RE4, I', going to save it for other games like AC Revelations, RE ORC, etc.
Even RE4 HD is not gonna have it..?Definitely (since mine got stolen) but it's such a pity that they don't have multiplayer or co-op mode online for mercenaries.