I think there is enough interest to make sure ubercart in its current form works in D7 to get the community to participate in porting it. Perhaps another weekend sprint would help get that going.
My basic concern about ubercore is timing. This time around, D7 will not only be complete for the core, but most modules will be working on it as well. Ubercart is becoming a critical component of many drupal sites, and shouldn't be left behind. People will be developing sites in D7 come Jan-Feb. We can't wait for ubercore to come out in Mar or even SF the end of April.
I agree about getting some outside help to port 2.0. I think there are a few of us who've done this, and setting up another launchpad project (similar to d7cx-views), since ubercart already is in bazaar, would be quite efficient in the port process.

A good port to D7, followed by an upgrade path to 3.0 would be a good next step. That way, people can easily update their D6 uc 2.0 sites to D7, and those on D6 waiting to update to D7, ubercore 3.0 next summer will also be able to upgrade without too much hassle. *fingers crossed*