I was starting to look around at various low-wattage tube amps from Bugera, VHT and the Fender Champ when I stumbled across the ZT Lunchbox amp. While it's solid-state rather than a tube amp, it fit the bill for me combining a great tone in a small package. And despite it's lunchbox size, this thing puts out an incredible 200 watts (135 RMS). I've jammed with it and it can keep up against a drummer, bass player and a guitarist with a 100 watt Marshall amp. In fact, it's got room to spare.
Just how loud is a ZT Lunchbox? Well lets just say it's loud enough for ZZ Top so it'll probably be good enough for you. You can see two ZT Lunchboxes in the photo below, just below the drum riser.
Despite it's small size (6.5" speaker) and diminutive weight (under ten pounds) this thing cranks! And the tone is excellent. While the controls are a bit different than what you're used to (ambiance instead of proper reverb, gain works a bit different) the tone you get is rich and tube-like. And if you want a bit more crunch, just put a Boss Overdrive or Tube Screamer in front and you'll have an easy to transport setup that you can use in the home, studio or on stage.
You can find these at some shops or online at Amazon and elsewhere for around $260 for the Lunchbox or $460 for the larger Club model which has a larger 12" speaker and comes in around 22 pounds.
Here's a short video I shot that demonstrates the ZT Lunchbox. However, the sound conditions were not ideal. The true test of the Lunchbox is when you see it holding its own in a live gig situation.