I don't know, it just seems presumptious and douchey to me to make an assumption that your instructor is actually going to promote you. Buying a ranked rashie or shorts without all ready being ranked seems taboo to me. I wouldn't even consider it, even if given permission.
I agree with this. Not to mention, I think stocking up on blue belt gear while you're still a white belt takes some fun out of getting promoted.
This kind of reminds me of how I want a pair of the BJ Penn RVCA shorts. Those are probably my favorite shorts of any I've seen, but I just can't bring myself to get a pair. They only make those with the black belt. I wonder who they're selling all these shorts to?