Do you want to know how the CSS WG works? Fantasai has written about:csswg, An Inside View of the CSS Working Group at W3C.
box-shadowfrom CSS Backgrounds and Borders Level 3: work on
box-shadowoutside the module for the time being, possibly re-merge with draft later. Rationale: drop-shadows seem to need a lot more discussion, but the rest of the draft is ready to move on.
border-imageresizes to fit small boxes the same way as
border-radius(proportional in both dimensions)