Bob, if you can stretch your budget ... here's a great deal on a new Genz Benz Shuttle 6.0 with a 2X10 cabinet.http://www.ebay.com/itm/Genz-Benz-Shutt ... 055wt_1324
They are usually $1299 at MF, etc.
I have this bass amp for my rehearsal studio. The head is 600 watts into 4 ohms and weighs about 4 pounds (class D power). The tone shaping controls are excellent for bass, it has a 12AX7 tube in the preamp to warm it up, and it's also very useful as a standalone power amp using the Aux In jack; I used it as a backup to my Focus 12R for my old Playing Dead rig and it had plenty of clean power to drive the 2x12 with E-120s, so if your guitar amp has a preamp out, you can make use of it in other ways. Also serves brilliantly as a direct box for recording, either direct or using the tone controls and tube (switchable). The whole thing is about 35 pounds or so and easily carryable with one hand, and has little legs so you can tilt it back if you want.
The 2X10 is punchy with plenty of bottom -- I have a 5-string bass -- and I even did an outdoor gig with it on bass and it was plenty loud enough. In a practice room, more than enough power to shake the house.
Scott uses the bigger Shuttle 1200 in Playing Dead, and he loves how it sounds. They also make a Shuttle 3.0 which is 300 watts and no tubes, but I haven't played through that.