As much as I want to encourage you, thulben, to make a a GCS-to-token converter, I really should caution you against spending too much time on the project just yet. While the framework is still in beta, I may need or want to refactor the token structure somewhat, and I'd hate to see you waste your time targeting data structures that are still in flux. I already know, for example, that the armor DR data structure will be refashioned when I include damage-type-specific DR. I also still haven't settled on a final JSON structure for spells or multi-round conditions (shock, stun, burning, and the like) despite a fair bit of work last spring.
With that caveat, I'd welcome any converter work you feel you can do. I'm a GCS user myself, so I'd be happy to test.
I understand that the internal data structures aren't finalized. Still... looking at the xml within the token, the difficulty is in getting information into that format rather than the information itself. I promise I won't get mad if you change something.
As for submitting changes or improvements to the framework in general, what sorts of improvements do you mean? Because of the SJG Online Policy, we can't add some of the most obvious improvements - combat skill check, active defense, and damage calculations - to the publicly available framework. If you have other sorts of code changes, just post a general description here of the changes you've made, so that people can make suggestions and ask questions. I'll set up a better way to exchanging code next weekend when I have a bit more time.
I added an onTokenMove macro and added an action chooser (or, perhaps more precisely made the one that you already have available to non-GMs). I don't know if these violate the SJG TOS or not.