Just a small update this week. This weekend I mainly worked on adding the layers and controls for tops, then trying to draw something that looked reasonable across all of the breast sizes. The screenshot has a sketch of a t-shirt which just about works, and hopefully I can get it looking better once I draw it properly. I also added a couple more bottoms, and spent some time trying to get rid of the movement bugs people mentioned.
If I can get a t-shirt that looks good, I'll release a version with tops next week.