Maybe something like this?
http://www.gumtree.com/p/for-sale/an...ece/1078011798
Looks kind of neat even though the ad mentions that it is an industrial piece ... and of course it is too far away and too expensive for me! But maybe it would be great since industrial sewing would involve a lot of long sitting periods, I would assume. Looks like the height is adjustable kind of like a piano stool. Oh, maybe that is what would work well .... a piano stool?!?! pennycandy did mention a piano bench so maybe look for a stool although I think I would like some sort of back piece. Ah the search is on!
(Champanier: I could not get your link to open to any pictures of people sitting in chairs.)