I have one of those for my Husqvarna, and they may make one for other machines, since it's not "fit" to the machine. It cost somewhere around 100 dollars.
I do NOT have the stitch regulator (that was an extra 500+ dollars).
What it is is a metal platform that moves very easily (alomost "frictionless") in 4 directions, with a small opening (smaller than a piece of paper) for your "work area".
It takes some getting used to, and you have to adjust the position carefully (I have masking tape on the base to know how to position it under my machine) otherwise you'll break your needles because you forget and try to sew through metal (yes, that has happened to me sometimes).
Working with larger quilts (like single bed size) is a bit of a wrestling match and it doesn't help a whole lot with those, but with smaller pieces (like the photo below), it's EFFORTLESS.
It does take quite a few hours of practice to get the hand/foot coordination to get the stitches even, but that's true for all FMQ. It's much less tiring on the arms to use than to use the flat acrylic table extenders.
I talk more about this piece in my blog.
http://quiltiliciousjourney.blogspot...-practice.html