Kingdra/Machamp(SF) has been a solid choice for a while now.
Others are Kingdra/Gengar- Kingdra gives you the extra damage often needed to score cheap KO's with "Shadow Room".
I dunno... Kingdra (LA) and Magnezone Prime might be interesting. In addition to being a backup attacker, "Magnetic Draw" can re-fill your hand after discarding a few times with "Dragon Pump".
You could try Mew+Rhyperior+Kingdra- LZ Rhyperior X, "Hard Crush" as many water energy as you can, and then when you need to "Aqua Stream" for massive damage and deck re-stocking.
Out of all of these ideas, Straight Kingdra and Kingdra/Machamp are still the best.