Since feature requests are coming in, I've decided to maintain a parallel version of the gCensus app where I develop new features. You can find it here:
So far, the only new feature I've added in the beta client is the ability to map multiple regions in the same KML file. This lets you (for example) compare multiple regions while having the same bins apply to all of them, which you couldn't do before. There are some rough edges, like the unbounded growth of the top (status) pane, and incorrect titling in the KML file, but you're welcome to try it out.
Keep in mind that this is the dev site, so at any given time it might not work quite right. Of course, if you find bugs or have feature requests, send them to email@example.com as always.