Hiding Ceiling Register (Vent) & Cold Air Return

[tilallr1]

Any tips on hiding these?

Since I am painting my ceiling black I was going to go with a plastic vent for the ceiling like so:



Also I was going to purchase something like this:

For the return air and paint it dark red to blend in with the walls. Since they are paintable.

Both of these solutions should make it invisible when the lights go out, but I am curious if anyone knows of any better way of hiding these sorts of objects in a Home Theater.