I just got an email from Natchanis with a picture of his new Overdrive Reverb chassis. If you're interested, please shoot him an email. [natchakom@hotmail.com]
I had the same problem. I think the chassis is punched for a 100W Fender PT. I used a 50W Bassman tranny but had to mount it with large flat washers. I guess an adaptor plate would have been nicer but I was too lazy to fabricate one.
As far as I know, Natchanis only builds an ODS and an ODS Reverb. You might want to drop him a line and ask if he does any custom fabrication. He might go for it if we had enough buyers on this forum to make it worth his while.