You're not going to believe this: My first attempt to breed a DW Eevee has yielded another DW female Eevee! That's like a 5% chance of that happening!
My only issue with it is that this one has one of the worst natures that a Pokémon could have (lax, the other is gentle.) Still, I feel that the Pokémon breeding gods are smiling down upon me.
So... you've got another choice: you can have that one be your Vaporeon, or I could try for one with a better nature.