http://caswellamps.studioelectronics.com/products.htmlHere's his company, and he does do the #39 mod that everyone always talks about ... being the mod that was performed on the #39 Amp from SIR, which Slash borrowed (stole) from them.
He also sells amps built from the ground up using the same wired setup as the #39. They aren't cheap but they're the only amps you'll get that can replicate that Sweet Child O Mine sound.
Thought the musicians here may be interested
Love to all
xo