There are actually quite a few Jubilee combo amps on Ebay right now. Most are asking for around $1200, which is about what people will pay for them. I'd say $1000 is a good price, and $1200 being fair. Anything more than that and I'd seriously consider getting a brand new Ceriatone Jubilee in whatever form you want. Are you planning to blend amplifiers ala Joe or using them in mono? If you plan to use a stereo amplifier rig similar to Joe's I would recommend trying to match your wattage by getting the 2550 model Jubilee. If you give up interest in the Jubilee I would recommend trying out the 2266 Marshall Vintage Modern. I really think that would be a great compliment to your 2204 because of the heavy midrange that the 2266 has to fit between the great lows and highs of the 2204. Not to mention it's an entirely different flavor of Marshall with those KT66's in there (more of an old Blackmore, Clapton, Hendrix sound). Good luck man amp GAS is one of the hardest to pass.
'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.