I contacted the developer who is working on the D7 UC3 release and his recommendation at this point is to hold out on releasing a D7 version because UC3 is "constantly changing". He said he was able to get it working with an old dev version, but things have been changing so much that he is reluctant to post anything yet. He would like to wait until UC3 has a stable release (which according to the UC maintainers, won't be until the required modules release stable i.e. views, rules etc.) before releasing a production version of UC Combine Shipping
@redcam, what are your thoughts on this? Do you still want a D7 version, knowing that updating UC3 might break the combine shipping? Or are you still good with waiting until (hopefully the latest of) this summer?