Ability to add meta box types defined (by plugin) to post types in the same way that you add taxonomies?
This is in my future plans, but it probably won't be included until WordPress 3.1 is out. My goal is to simplify the handling of meta boxes in WordPress so that they meta handlers will register with WordPress allowing other plugins to know there there. This will give CMS-Press the API to see what meta boxes are available to support.
Ability to create meta box types through a separate form under CMSPress (which then could be added as above
I haven't completely decided yet. Once the meta box handling is improved in core, I'll see how well other plugins out there that allow you to create custom meta boxes are using it to see if I need to add that to cms-press or just suggest to also add plugin X for building custom meta-boxes.