i don't know if this has been suggested but along the lines of a room divider what about getting a cubical wall. they are almost always covered in a fabric/carpet that would hold the blocks. and you could always pin them. I think that maybe getting those old medical records filing cabinets to store your fabric on would be nice. you could paint them or cover them in fabric if you wanted too. I would "hang" your quilts on the sloped ceiling when they are done or waiting for binding to be put on for finished. that way you will remember which ones are almost done and you don't have to fold them up.
you are really lucky to have such a large work space to sewing. I would love to have one that large. well i would love to have one period. i use a corner of my living room to store my stuff so the kids don't get into it and then when all are asleep expand out into the living room. good luck and show us pics when you are done.