Gordon, At this time, we've not ported HTSQL to Python3. That said, we did most of the work (unicode conversion) a few years back. We have an internal fork at Prometheus we could share if you'd like. Also, we're happy to make the license MIT/Apache.
At this time, the Python/HTSQL isn't going to be improved. We are working on a next generation tool you might be interested in https://querycombinators.org -- we will have a release of this for Julia sometime this summer.