For your info:
In the german magazine "Gitarre&Bass" from june 2009, page 270, I saw the following add:
Translation of text (probably not really needed, but just in case)
"Original Dumble overdrive special combo, good condition, new tubes, price suggestion EUR 22,900. Can provide more info per e-mail: dumble@loop.de, Telephone +49 179 4989 172."
Not exactly cheap: 22,900 EUR = 31,866 USD, but probably market price. John Mayer will surely give him a call anyway
