I have one made by Greer, called sewing mates. It is super, super. It adjusts for ANYmachine- from my Vintage to my sit down Bailey. It is so adjustable. It is stable, has aluminum legs and is made in the USA. I got it over a year ago and use it everyday. Has a variety of sizes, I have the largest.
http://www.sewingmates.com Bonnie Hunter recommended it.