David the one published in QQ (QRPQuarterly) back in 2006 and was a 1W design SSB only.
I've done 5 others but those are not published and my notebooks while complete are not a
"here build this".
Doing 6m radios are not not going to use many 3904s save for an IF and audio stuff. Once
you at 6M RF devices suitable are needed.