this topic has been discused many times! My DH make this set-up for me. He took an onld table and cut the legs off to make the height tat was ergonomically correct for me (chair height and added platform height). He then followed the instructions on this video ad made me the sewing table. I keep it up all the time and use it for FMQ and general sewing. It is GREAT!!!!!
http://www.youtube.com/watch?v=g14govA4pIM