Big no. The only way I think it could work is to to change up the way the evolutions are set up.....it'd almost be a new pokemon at that point and too complicated.
It just might work....but I feel it should only happen from eevee, not vaporeon say just gaining another type. I'm not completely sure what items would be used, but eevee is supposed to adapt according to it's enviroment right? What if that said enviroment was home to more then one element?