Ask HN: Is a Bitcoin 2 feasible?

I'm curious, how feasible would it be to create a second currency almost exactly like Bitcoin (say Bitcoin 2) with the only difference being that its a new market (aka the barrier to entry for mining isn't so high)?

I haven't really been following bitcoin that much so forgive me if the answer is obvious. It seems that if Bitcoin can be successful (at least to the degree people are trading large amounts of money with it) then there should be copycat currencies popping up based on the same principles.