Since the "hit box" drawing itself does not add bloat and does not slow down rendering when not enabled, I added it for next release.
As for the coloring stuff (currently for mini-map dots and/or name tags, but the hit box will use the same color as for the mini-map dots), it's already there, just "hidden" (no hard-coded UI to use it). See the
Lua sample script and how it uses LuaPieMenuSlice(), OnLuaPieMenu() and OnAvatarRezzing() to implement a simple UI based on the Lua avatar pie menu (SHIFT + right click on avatar).