You could always use the luxuries option to increase the size of a standard stateroom. If you want a 10 tons suit, buy 2 4 ton staterooms, and add +2 tons of luxuries....viola.. 10ton luxury stateroom
Want a basic berth..buy a barracks and call it a berth. the fluff text says no one will travel in such a primitive set up..but if you change the fluff text...and document it...presto a basic berth, a bed+small desk, storage locker nothing else...common fresher, add one ton luxuries as a common shower/fresher.
if you want to just use the luxuries headings for extra room and such, without adding the +1 to steward level feel free...you can say it just makes the primitive furnishings livable.
Here's what I use for my own use....
Bunk,( acceleration couch) a Bed, storage locker, in a small niche shared fresher for all bunks. prepack, or self supplied meals..surplus MREs anyone...
Berth,( barracks) a bed, in a small cubbyhole, with small fold down table/desk shared fresher small common room can be bought as a coupe of tons of luxuries and shared by berth passengers. slightly better pre-pack meals....mmmmm hungry man dinners.
Stateroom: as written
Suite: 2 staterooms, for bigger ones I add a few tons of luxuries.
there are write-ups for shops ans stuff, you can use the same process. by using luxuries( call them upgrades)...but add a +1 to a skill if you like....