I purchased a "drafting chair" to use with my quilting set-up. It has wheels, a bar around the lower end of the center pole to put your feet on and is adjustable to the right height. I have lamanent flooring on top of the carpet in my sewing room so the chair will glide smoothly. I can sit and push the chair with one foot from one side of the quilt to the other. This might be a good alternative for you.

I am very vertically challenged and have bursitis in the right hip...once I had the ergonomics worked out for quilting on my shortarm and now on a Bailey Pro 17E with Grace Majestic Frame, I needed to raise myself since the frame was as low as it could be. I used a few layers of interlocking floor mats (the number of layers needed depends on your height). You can use any number of mats to fit the width of the frame and then build up the layers until you determine you have reached the right number of layers. I rarely have pain in my hip, back or knees. Hope this helps.

There is a saddle type stool on wheels made for quilters who can't or don't want to stand for longer periods of time. I'm sure one of the LA magazines would have a link ... or you could search for it on the net.