I am a black belt in Shaolin Kempo and went to a Shotokan Dojo, mostly out of curiousity, and I was told that, due to my current rank in Kempo, I would start at brown belt in Shotokan. The way I see it is this, the early ranks in martial arts are to ingrain the basic skills into you - strikes, kicks, slapping out, rolling, etc... and tend to be fairly similar throughout martial arts as a whole. When you already know how to throw a thrust punch, or a shuto strike, or a roundhouse kick, there's no point to re-learn it. Skipping belts without previous training on the other hand, I don't feel that is right.