there is hope when it comes to 'box' rooms..
My family has lived in a 1930's semi since 1983.. 3 bedrooms, but in reality it was 2 bedrooms and a box room. 1st Bedroom is quite a good size, double bed 2ft of space along one side of it and 4ft on the other, enough room for 2 walls to have floor to ceiling fitted wardrobes with around 3ft of space leftover for walking around. 2nd bedroom, should really only have a single bed in it, however we squeezed a double in, one wall of fitted wardrobes, a space about 2ft by 6ft to 'walk' in is all thats left.
the ''3rd bedroom" is 6ftx9ft! (I've seen walk in closets bigger than that in the US!) only a single bed will fit and there was about 3ft left for a wardrobe and thats it.
what we did in there was make a fitted floor to ceiling wardrobe, and over the bed bridging units with doors and shelving area underneath. All the stuff that usally would have been on the floor now fits nicely in those - leaving the small area left just to stand, get changed and check yerself out in the mirror in relative comfort! it's the best 'clever' utilisation of space we could think of in that room and surprisingly, lengthways against a wall there is even a 3 drawer dresser/bedside cabinet which is around 2.5 ft wide but the drawers only open 75% of the way before hitting the side of the bed! - we were proud it even fitted in!
a tip leading from this, although we 'permanently' fitted the wardrobes, prior to that I installed myself a similar setup from ready made furniture, obviously space at the top was wasted, but it did hang nicely for 10 years! - so you could do the same on a budget/rented place so long as the landlord allows you to drill into the walls to hold up the bridging units. Even if the have to come down, it's easy to fill the screw holes with filler and paint/wallpaper over again easily.
Hope this helps !
DtM! West London & Slough UK!