It would be really useful if you could map the Vault Lifecycle state to the Drawing. This would be useful as a visual ‘stamp’ whether a Drawing has been released or not.
This can be done today. You simply need to build the mapping to the Inventor iProperty of your choosing for the "State (Historical)" property. You will need to be using Job Server (running as an account that has read and modify permissions) in order to ensure that the stamp will get visually updated for files that are in a Released/Locked state.
Doing the above, you can get exactly what you are looking for; a note on the drawing that shows the current state.
-Ryan
FYI...if you use items, this kinda does it for you. It doesn't mark the CAD file, but does mark the dwf anytime you view a file from the item.