A good clone of a model T or 1200's cranked to full on doom would be amazing
Laney Klipp & Supergroup:
Early Black Sabbath tones, I have one of the Klipp that is okay but the Supergroup would be great, A Klipp with the Klipp circuit engaged and cranked up would be awesome.
These guys make really interesting amps, sort of heavier high gain voiced but with good midrange, The Skyhammer and Meatsmoke are both awesome. I know a guy that has a Skyhammer so I may try to borrow it and get it done.
Electric Amps USA:
Originally the US distributor of Matamp's, these things are crushingly heavy doom machines and rare to come by since they aren't really made anymore, the MV120 would be amazing.
Fender Tweed Twins HP and LP:
John Mayer PRS Head
Greedtone JHI 100