Originally Posted by Yarn or Fabric

If you are handy, you can make one. I'm almost positive I saw here someone who made one.

http://www.instructables.com/id/Chea...Table-or-Desk/

http://www.squidoo.com/sewingtable

here's a discussion about what others have done to make them...
http://www.straw.com/equilters/libra...wingtable.html

I know I saw somewhere that someone made one here though.
Here is a thread talking about a particular computer table used for sewing... several people got these...
http://www.quiltingboard.com/t-53791-1.htm

Ahhh! Here it is!!
http://www.quiltingboard.com/t-41371-1.htm
She used 3 pieces of pvc and puzzle pieced then taped them together. It's rather ingenious and incredibly creative.

Here, someone used a desk that was free to make one. She gives a bit of details on how she did it...
http://www.quiltingboard.com/t-43796-1.htm

Here's an extension table made from wood and she gives details on how to do it...
http://abkcreations.blogspot.com/201...ion-table.html

and a tutorial on how to make a wood extension table...
http://oleniczak.com/wordpress/?p=57

There's a slew of tutorials on how to do this. I'm going to start making a list of links on my personal website this morning...