from my knowledge, the former magical key is now called the universal key. originally it was intended to open all mission doors, but there were too many problems, so that property of it was eliminated. it is one of those items, like the wonderflask and whatsitsname, that can be aquired, but not sold. it is apparently (according to sandy's site) still called the magical key in the supply tent, levels 42-44 (45 and 46 possibly, they're not on the site at all yet). v said he'd be looking into that on monday. hope that helps.
--jason