I honestly don't get why Toriyama said he didn't know what a female Super Saiyan would look like. That's got to be the dumbest excuse I've ever heard.
He didn't want Female super saiyans to be a carbon copy of male super saiyans. It would have been easy just to make Pan's hair Yellow/Gold and give her green eyes. but he wanted it to be "Different" but just couldn't find a way to do that.
To be fair, he had little to do with GT and we've since had female Super Saiyans in Heroes and Xenoverse.
On top of that, it was officially stated recently or sometime ago that if Pan were to become a Super Saiyan, she would be a completely unique Super Saiyan never before seen or something. Probably because of inheriting Gohan's hidden potential.