I picked up an original vintage Blackface Bassman head for $300 dollars 2 years ago. According to the GP article on the album he used a Blackface Bassman + Vibrolux with an Xotic Effects X-Blender to create an effects loop for those amps (they don't have loops). I believe he mentioned that he had a TC SCF Chorus, DD-3 Delay, and possibly a reverb of some sort running very wet through the X-Blender and just using the blend knob on the X-Blender to add the effects to taste.
http://cgi.ebay.com/FENDER-BASSMAN-BLAC … dZViewItem
http://cgi.ebay.com/Fender-BASSMAN-Guit … dZViewItem
http://cgi.ebay.com/VINTAGE-FENDER-Blac … dZViewItem
If you don't like to buy off of Ebay you can look in your area for any guitar stores that sell vintage/used gear and without fail most of them will have old blackface and silverface amps. You will probably need an attenuator for bedroom tones but if you gig I find that the 40-50 watt rating on them to be about perfect. For other alternatives, check out the Metro JTM45. My father built one and we AB'ed with my Bassman...surprisingly similar!
'67 and '74 Fender Twin Reverbs, '74 Marshall 1987 lead mkII, Metro Superlead 100. Pedals from TC Electronic, Ibanez, Dunlop, BK Butler, Electro-Harmonix, Fulltone, Maestro/Gibson, Loopmaster switching, VoodooLab, Boss. Gibson and Fender guitars, Dimarzio pickups.