Audio Advisor sells Vincent Amps - hybrids rated 300wpc into 4 ohms and advertised as stable into 2 ohms. I've not heard them, but they meet your criteria.
Hybrid amps that can play 1 ohm loads
I have Apogee Scintillas and am looking for a modern high current hybrid that can play a one ohm load and still maintain the beauty of tubes in the midrange. This will take an amp with a heavy duty power supply that still can sound like music. Any ideas would be welcomed. Bob