If we are to believe that in StarTrek we have the PA's the small combat ships that was mentioned in a post some years ago, then I'd like to throw in another idea. Why would a combat ship need a "bed"? Though we have bunks for the sailors on every naval vessel to date, in the old days of steam and sail, the beds were just hammocks strung across a room for the crew to sleep.
In a combat ship, getting out of bed half naked, and trying to put on your clothes when the enemy is attack is kind of a bad idea, so I was just thinking. For the ships of the Defiant class or the Perimter Action Class ships, why couldn't the regulations have it to where the crew does sleep in hammocks, and is dressed in Jump suits, instead of a regular Starfleet uniform.
Sleeping in a hammock and the klaxon goes makes it easier to jump out and get to your station instead of having to worry about running into a bed in the middle of the night when you only have battle lamps shining, or having to worry about finding your uniform when you're sleeping in skivies, and trying to dress in a hurry.