I thought about selling them but I think the cost of the final product would scare people away. You have to think that it's $10x2 for the Official Nintendo cables + $5 for shipping from them. I'd want to add at least $15 to transaction for myself to cover my time and the supplies needed. Add shipping onto that and you've got a cable that ends up around $45! Unless there is very high demand I simply can't see people paying for that (although I guess I did).
I'm hoping that someone can find a better or cheaper way to do this. It really is a shame that Nintendo doesn't seem to be supporting the Micro very much. Obviousily the demand for a Gamecube->Micro cable is the same as the demand for the Gamecube Component cable in their eyes, as unfortunate as that is.