Dawkins, like any responsible scientist, has always conceded the very remote possibility that their might be a deity. If you wish to be scientifically accurate, you have to concede that their might be a remote possibility - its just very very very very very very unlikely.
The Invisible Pink Unicorn that modeller describes is very like Bertrand Russells Teapot, or The Flying Spaghetti Monster and the religion of Pastafarianism described by Bobby Henderson. They serve to illustrate a philosophical point - that the burden of proof rests upon those who make unfalsifiable claims, not the sceptics or those that reject such claims.
The only difference between the well known religions - The abrahamic ones, buddhism. is quantitative - length of time they have been around, and the number of the faithful.
http://en.wikipedia.org/wiki/Russell%27s_teapot