Out of all those still out there, I think the least likely would be Dragon, Ghost, Bug, Flying, and Fighting. An Eevee with wings? An Eevee with fists? An Eevee with an exo-skeleton? An Eevee that has passed on? Sorry, I just don't see any of these happening, heh.
However, I could definitely imagine a Poison, Rock, Steel, and Ground type Eevee. The latter would be sandy, possibly evolving from a Sand Stone, or during a Sandstorm. I just have the image of a Hitmonlee-coloured Glaceon. XD