I then noticed that the store had a JMD-1 100 watt head and so I tried it out through a 1960. It sounded pretty good, and didn't have any of the compression/dynamics issues from the spider valve. There was also a JVM next to it, so while the JMD1 tones were fresh in my memory I played through the JVM to see if I would notice any any glarring differences and I didn't. It seemed like maybe the edge of breakup tones were better in the JVM but otherwise they both sounded great.
So the new Marshall JMD-1 looks like it could fit the bill, plus it has sweet side handles for the load in/out.