Hi. You have a real issue that requires more attention. You might consider re-posting this in "design dilemma" as you are in "other" and that may get you more help.

You may also want to consider a screen or pass-through bookcase to visually divide the "bedroom" area from the living area. I like your table and platform bed ideas. Consider whether the radiator will have enough room to "radiate" with a bed against it though. www.twitter.com/216Sharon

Got an IKEA nearby - they'll solve this for you!

No sunken anything. Miserable to vacuum and place furniture and tripping hazard and soooo dated. There are lots of house plan books you can get in the magazine section of Barnes and noble. I would start there and then consult an architect when you are clearer on what you want.