How about hangind sheers from the ceiling to create separation without bulk? I would use either thin metal drapery rods or you could use plumbing pipe for a much cheaper alternative. Get elbows, attach to ceiling & put pipe between - this will drop it enough to be able to move if you need to. Attach swing arm wall lamps on each side of bed & get floating shelves (very small!) for each side as night tables. Put the kitty crate under the shelf on the closet side. You could also use a solid drape to coordinate with your living area (which, BTW, I love!) or one drape panel at wall with sheers the rest of the length to seperate it from the door, but not the living area entirely. Not sure if platform is the bed, or a solution you came up with, but you may want to go to a bed frame - in your place, those extra few inches will matter! It could be raised a little higher for storage, or you could get a bed with storage drawers underneath - always a good solution for bulky items that are hard to store (like blankets, comforters, winter sweaters.)

A natural fibre room divider. [houzz=]

Try a track mounted to the ceiling for suspending a curtain.

Have a look at this clever renter and her DIY tips on creating nifty room dividers:

I think these ideas might help you but I love what you've done to the place so far, especially the living room! I also think you need a rug for the bed area and new paint color for the walls of your 'bedroom' I'm thinking blue.. http://www.houzz.com/photos/modern/studio-apartment-room-dividers-