Our goal for this stuff has always been to "keep it close to core." Multilingual problems aren't something we're generally equipped to solve, but there are a lot of other people in the community working on it. Ubercart does its part by using the core Drupal APIs for localization as they're intended, so any solution that works with core Drupal will work with Ubercart. I'm not sure what else we can really do at this point.