A Fender Tonemaster (Deluxe or Twin) can do Jerry tones about as well as a tube Deluxe/Twin can. I have the Deluxe and it's definitely grab and go! 22 pounds!
The Tonemaster Deluxe has been superceded by a Milkman The Amp 100 into a Coscia 1x12 with a JBL K-120. The whole thing is about 35 pounds total. Not perfect grab and go, but definitely lightweight, portable, and KILLER tone. The Milkman 100 is flat-out amazing. I use it mostly with pedal steel, but it's an excellent guitar amp as well. Crank the treble, drop the bass, and it's instant Jerry. The boost circuit is nice, too - it's a MOSFET between the two tube stages, so the guitar always sees a tube, and the boost acts more as a fattener than a high gain circuit. I can run it always-on with a pedal steel with no overdriving issues.
Better yet, Coscia has started making a "Milk Crate" cab that houses a Milkman head in their 1x12 Hard Truckers type cab. I may well get one! Turn my setup into a combo. A 15" cube with classic Hard Truckers look as a combo that sounds monstrous? Yes!
I've also been experimenting with speakers to cut weight (and reduce risk to my precious JBL). I tried a Celestion Copperback which is only 5.5lb. It's not as good as the JBL (harsher highs, thinner low mids), but it ain't bad, and it trims a full 9 pounds from the weight. I just got a Weber Neomag 12 (cloth surround, aluminum dome of course) that is a couple pounds heavier than the Celestion, but definitely sounds smoother and more full in the low mids - critical for pedal steel, maybe not so critical for guitar.
Anyway, that would be my grab-and-go formula - a Milkman 100 mounted in a Coscia Milk Crate cab, with a good neo speaker (or a JBL if you wanna be purist). Under 30 pounds with a neo speaker, around 35 with a JBL, big pro-gear metal handles. I don't think you're going to get closer to a SMS-Mac-JBL setup than that, for the weight and size.
