The Polk Lsi series drops down to as low as 2.5 ohms in the woofer range, NHT Classics are about 4.2 ohms across the woofer band, and the Revel Ultima series run about 3.8 ohms. These are among the hardest speakers to drive recently made that I know of.
A solid 2 ohm load across the woofer band would be extremely rare and you would probably need some huge monoblocks for that.
As far as a fully 2 ohm stable receiver (capable of driving a nominal 2 ohm speaker), I can't name one off the top of my head. I don't think even think Yamaha RX-Z11 or Denon AVR-5805 could handle that without the protection circuit kicking in.