(http://i31.photobucket.com/albums/c356/StebenDerMeister/vibrafet.gif)
Thinking of the Fenders...
Could this work, once you bias the controlling fets (at the source) correctly?
Well, it won't do what the Fender amp circuit does.
You may want to re-read my posts. I was incorrect in my first posting - the filtering is not a simple one pole RC/CR filter. It's actually more like the two halves of a twin-T, although not exactly.
In addition, I think there will be some pretty big feedthrough that is not cancelled. But it's a simple circuit - go breadboard it. It may well have hidden beauties.