I have a few deck lists with Empoleon in it, so here is one of them:
Pokemon:20
3 Piplup
3 Prinplup
3 Empoleon
3 Trapinch
2 Vibrava
3 Flygon d
2 Flygon d ex
1 Ray ex d
Energies:15
4 Delta Rainbow
5 Water
6 Psychic
Trainers:25
3 Holon Mentor
2 Bebe's Search
2 Celio's Network
3 Windstorm
4 Castaway
3 TVR
2 Steven's Advice
4Rare Candy
2 Strength Charm
Strategy is to start off with Piplup, spread damage with Prinplup, then clean house with either Empoleon or Flygon ex d. Ray is in there for additional sniping, and counters Gatr/Empoleon.
And here is another:
Pokemon:20
3 Empoleon
3 Prinplup
3 Piplup
3 Octillary
3 Remoraid
1 Absol ex
1 Mantine(DP2)
1 Mantyke
1 Eggs d
1 Eggs jr. d
Energies:15
3 DRE
2 Scramble
10 Water Energy
Trainers:25
3 Celio's Network
3 Holon Mentor
2 Steven's Advice
2 Team Galactic's Wager
3 Castaway
1 Scott
3 Battle Frontier
2 Glacia's Stadium
2 Super Scoop Up
2 Warp Point
2 Cessation Crystal
Strategy: Bench hitting, disruption(Wager and Octillary's first attack), and using Absol ex late game to KO their heavy hitter(Using its power and either Empoleon or Octillary). Mantine is for the Free Retreat body, and Mantyke isn't that bad to start with.
Try one of these out, and see if they work or not. To tell you the Truth, I still need to test the Flygon version.