Recently I found some photos which seem to show Jonny using a Marshall Cab on stage at some point. You can also clearly see it in many photos of him in the studio (with a good example being the "jazz" video). It seems odd he would use something of higher wattage the his Deville's in the studio, and I can't find anything on this in any published info on his setup. Am I going crazy:stunned: or has he actually had a Marshall at some point?

Yes he d(id)oes, guy also use(d) Marshall amps.