I have constructed a single ended MOSFET amplifier, similar to Nelson Pass' Zen amplifier. I have made some power supply changes and some input and output changes. This amplifier sounds very good with the Quad ESL's. My version of the Zen produces about 8 watts per channel.
The schematics and parts list can be found on my Audio Schematics Page
Here is the reference to Pass' two articles on this amp: