well there's a problem with making more eeveelutions. all of the eeveelutions have 2 good stats, and the rest are fairly decent. for instance, jolteon has good speed and sp attack, while vaporeon has good hp and sp attack. while leafeon has good defense and attack, glaceon has good defense and special attack.
the thing about the 2 good stats is that they must make sense for the pokemon, and must be different than the other eeveelution's stats. it makes sense for jolteon to have such good speed and sp attack because he's an electric type. it makes sense for leafeon to have good defense and attack because it's a grass type with physical matter.
if you were to make a flying type, the only thing that would make sense for a winged cat is maybe high speed and sp defense. since no other eevee evo has this combination yet, it could work. ghost type: it wouldn't work. besides, no moveset could work for a phantom cat. fighting type: it wouldn't work. same goes for a fighting cat... steel type: maybe. if it had a separation of 3 better stats (like espeon) between sp defense, defense, and attack/speed, then it could definitely work (and would be so awesome!!). a ground type: it could work. high HP and attack/defense. it just wouldn't be so interesting. a bug type: bug types usually have all-around decent stats. it could work, and would be fun =).
finally, normal type. we need one. now. and it needs to be awesome, with both high attack and special attack and speed. i always thought it'd be awesome if you could use the everstone on eevee, and though it's effect is to make it NOT evolve, eevee reacts different to it, and we get eeveeon.
