Yeah, sorry - I should clarify. I'm from Canada, and there we use the term 'backpacking' to mean hoofing it around in the wilderness, too. When I think of SE Asian backpacking, I just mean, going places. With a backpack.
I was looking at 40-50L ones, too.
Also, I'm so wary of buying anything on Gmarket, for fear that I'll get knockoff merch. Am I just being paranoid? It seems like Gmarket would be a bit sketchy to buy brand name things from.