The MindWave Mobile seems far more convenient than a dissected Mindflex. Thanks for sharing the link—I may need to get one myself. Achieving consistent electrode placement was certainly a challenge when I was working on this project.

I hadn't come across the Nekomimi yet but it seems as though Neurosky has figured out how to manufacture relatively inexpensive EEG consumer devices. Further, the Mindwave mobile seems to get 8 hours of run time off a single AAA. I would suspect a more compact implementation of the Nekomimi is quite achievable.