Farmers angry with the ETS are talking about setting up a "farmer party" to represent rural interests. Isn't that what the National Party is? But I guess that the farmers have finally figured out that the interests of National's Auckland business community donors are not their interests, and want their own voice. And as with the Maori Party, its up to them how they do it.
I should also point out that they've done this before, quite successfully. In 1924 the Auckland Farmer's Union (part of the New Zealand Farmers' Union, a predecessor of Federated Farmers) set up the Country Party, which held a couple of seats between 1928 and 1938. That was under FPP; under MMP if they can get a similar regional stronghold or a large chunk of their mythical 14% of kiwis who are "farmers" (by which they mean anyone who lives in a rural area), then they should be even more successful.