Ok I know it's a little against the rules, but I was playing around with gravity and there are some awesome opportunities for climbing maps there, as well as other type things. We might finally have some original climbing maps!
So why not just stick a float in the options part of a PMS file to hold gravity? It wouldn't be all that hard or time consuming to do (unless I'm totally wrong), nor would it be hard to make a quick change to polyworks to support it.