When Goichi Suda said last month that No More Heroes 2 would be the last of the series on the Wii, he didn't mean that was the end of its development on Nintendo. Suda expects a "Wii 2", and NMH to continue on that.
Although, speaking to 1Up, Suda also made clear that he's " finished the story for Travis [Touchdown] . It's completely finished in No More Heroes 2". Anything developed will involve "a different character, or something like that within the series — starting on the next Nintendo platform".
Suda's comments themselves don't betray any knowledge or certainty of such a console, other than the assumption that, yes, its day shall come. So for all of you who took this to mean No More Heroes as you knew it was done, the answer is no.
Actually, I answered differently, and it may have been misinterpreted. What I wanted to say was, looking at the Wii, I think No More Heroes 2 will probably be the last iteration for this current platform. But there's probably going to be a "Wii 2" or other next-gen system from Nintendo at some point, so I was saying that I would want to do another game in the series on the next Nintendo platform.
Goichi Suda Interview [1Up, thanks Joseph L.]