I solved my problems with a "drafting" chair. They are especially pricey, but I found one on WalMart site that was only $70 (a whole lot better than the hundreds wanted at office suppliers, other furniture retailers). It's padded and quite comfortable, large seat and adjustable large back, no arms. It does go quite high.
Here's the dilemma it solved for me. I have a mid-arm (Baby Lock Coronet) which I love, love, love. I far prefer to move the machine rather than the quilt (I had a sit-down before the Baby Lock). The frame only goes down so far and not anywhere near a sit-down level. Also, I am very short, 4'11", so my feet reach the footrest ring on the chair, but certainly not the floor. Not a problem, though, as the chair rolls easily across my hard-surface floor. I simply use the front rail to move the chair with me in it as the design dictates.
I have had a serious back surgery and cannot stand for long periods of time, but my $70 chair has allowed me to spend 4-6 hours at a time doing what I love.
Hope this helps.