Well I said I was working on one and here's a quick pic of the first prototype board...
It works fine off the bench supply but is a bit loss-y with the little 18V switch mode supply I got for it - the diodes and caps near the power rails are only necessary if you're using a battery supply so they've been eliminated... If I twist the bench supply up to 20V it's fine... I'm gonna try it as is with a variety of guitars... if I think it's too weak I'm gonna try throwing a little 2N5457 circuit in front of it tomorrow to see if bumping the input up just a little makes palatable difference... ideally I'd love to throw a tube in front of it but that means a much bigger PS... Hmmm....