I just tried teh 652.7i's (6.75" 2 way) in my car and wasn't too pleased with them.
The highs seemed overly bright. Mids were so so.
They ended up going back to crutchfield.
I don't know who else makes 2 ohm 6.5's though. One thing worth considering is if you can lose the balance, you can wire 2 4 ohm's in parallel to get a 2 ohm load.