My view is that the bulge is not related to any earpiece, but rather is a medical device needed to correct an undisclosed Bush health problem. I never bought the idea that Bush would use an earpiece in the debates. Such a device would be enormously distracting and would probably hurt his performance rather than help it. Also, it's just too damn big. I was in a club this weekend where the bouncers had earpieces and there definitely were no 'bulges' in their backs at all. However, there are a lot of medical devices that could account for the bulge, many of which have been discussed here on Daily Kos. Given the fact that Bush mysteriously refused to take his annual physical this year, it's certainly reasonably to suspect that Bush has some undisclosed health issues that, if disclosed, could affect voters' view of Bush's fitness for office.
Anyway, here is a good new article in Monday's New York Times on the 'bulge' story that will not die. The article also talks about how the 'bulge' story is symptomatic of Bush' isolation in the the 'bubble,' and how more and voters are concerned about having a bubbleboy as president.