One thing i loved in an old farm house we lived in years ago was the upstairs (we have a very steep pitched roof) and the farmer who had built the house used every bit of space he could for storage, building closets and cubbies into the walls where the roof-line sloped. Since you are at rough framing stage, keep in mind all the space that is going to be hidden by the walls and think of all those shelves of fabric you can put there! And Yes!!! lots and lots of electrical outlets, that way if you decide you want to move your equipment you are not limited to one or two walls or corners.