The superbrand concept is definitely interesting - I would like to see the 'religion' superbrand compared against another large cultural phenomenon and see if that has the effect of suppressing brand loyalty. My first gut reaction was with the environmentally aware demographic, but I actually doubt that would be a good comparison as a lot of companies have figured out how to capitalize on consumers' desire to be included in that group.
Another interesting thing at work here is to define what exact falls under the 'brand of religion'. There have been attempts to brand religion, certainly the practice is as old as selling idols/icons of faith. More recent examples include the WWJD tagline... I come from a Judeo-Christian background so I'm not familiar with other expressions of this sort of branding elsewhere, except where practitioners of faith choose to wear external markers. I think our culture tends towards pushing acceptance of multiple beliefs, so I don't know if the superbrand is as strong as it could be, and certainly in a lot of places being religious doesn't garner you any social acceptance. Life in high school would have been a lot easier if I'd had designer jeans instead of a religious conviction.
I had thought also that maybe the defining characteristics of the religious is that the very nature of what they believe would reduce their reliance on 'things of this world', therefore decreasing brand loyalty, maybe? However, there's certainly evidence out there (at least, for American Christians) that their belief system doesn't appear to affect their behaviors in other areas of their lives (the divorce rate is almost the same, etc.), so I struggle with that hypothesis a little bit. Very interesting topic!