Really? I'm going to get a custom cabinet to fit two Fender amp chassis, a 65 reissue Twin Reverb and a 1972 Bandmaster Reverb. I play through both wile I play and I love it. Instead of working with just one preamp, you have two to shape your sound. I set the reissue Twin Reverb on the clean channel Treb 7 Mids 6 Bass 1.5, so I get my clean sound with a good warm sound which sets the foundation of my sound. Then I set the Bandmaster Reverb on the reverb channel (it has spring reverb like no other amp around) treb 10 Mids 5 Bass 0, the bandmaster tops off the Twin Reverb's warm clean sound with piercing crisp highs and a natural bassy bottom the speakers in the cab have. One benefit of having my setup this way is that when playing, my dynamics can effect the level of the two amps, stretching from a real clean and direct sound to an extreme reverb sound, which sounds exactly the same as the ones you can hear on Europe 72' on "Jack Straw" or "You Win Again" when they were playing in those great halls and theaters. That's how I like my reverb. The Bandmaster Reverb really is what completes and makes my sound. I could replace the reissue if I had to easily but I'm not getting rid of the Bandmaster. That's why I wouldn't just take the easy route and get a sarno rack preamp because it's cheaper to use what I already have, and I can't imagine it being better than the bandmaster.
As great as this set up is, it's huge! The cab for the Bandmaster is so big I could easily fit 4 12" speakers. On top of the cabinet I have my Fender twin Reverb, and on top of the twin I have the Bandmaster amp head which is so big I could fit two 10" speakers in. A towering stack of amps and cabinets almost 6 feet high. So, with creating my new rig, all of this huge mess will be gone. I would have guitar > Preamps > Mc2105 > 2X12 cab (one preamp going to one channel feeding into one JBL E120 and the same for the other preamp). I will have the two amps once they are in the new cabinet serviced, turning them into preamps with all of Waldo's recommended mods.
Once I get enough money it will be all possible which will hopefully be soon.