I don't have a sewing room. I have a cell. Inmates have more room than I do. I started with a 12x12 room. DH put a 2.5 foot deep counter the whole length of one wall. I'm down to 9.5 feet. On the other wall I have an antique buffet that I use for storing linens and I use the protected top as an ironing station, it is 18 inches deep - I'm down to 8 feet. One whole wall is a closet where we keep winter coats and seldom used clothes like suits and fancy dresses.In front of the closet is my folding cutting table. With the leaves down it is 14 inches deep. I'm down to 6 feet 10 inches. On the other end opposite the closet, is my industrial machine. The table is from a closed sewing factory but it is smaller than the modern tables since the top is a solid slab of hard rock maple. I switch out my Singer 31-15 with my Pfaff 138-6 since they both use the same table cut out (Bonus!) The table is 18 inches deep, I'm down to 5 feet, 4 inches. In front of the China hutch that butts up to the buffet I have a large plastic tote for fabric storage. It is 20 inches deep, this leaves me with a total of 4 feet of open floor space. My chair takes up about 18 inches square and the 3 dog beds for my assistants take up the rest of the open floor space.
I have everything I need, but living in a 750 sq foot home really teaches you how to employ "creative stacking" and teaches you real quick what is important to keep and what to send on its way to another home.