I have been talking about turning this chest into a sub/center channel for years.
!! I think it's a great idea ! what I would do is build a down firing sub enclosure and have room for a cooling fan and amp in it too ! and place it elsewhere in the room,it would look great !!!!!!!!!!
you could rebuild and re-enforce the inside of thjat trunk and it wouldn't look any different on the outside !
and to ad to what WmAx said,put the CC on something else.