It's kind of both. We're three guys working on the code, but we also have to support the project w/ consulting work. We charge enough to cover costs for sponsored development, and the real benefit is that we can block out hours at a time where we take a break from the forums and don't schedule consulting work to just work on the D6 version. If you're interested, you can use http://www.ubercart.org/sponsors as a reference and contact me about what would be helpful. We generally let sponsors indicate where they'd like us to focus, but we're getting close to just needing to block out hours at a time for full testing and some documentation.