Please get off your knees! You will identify the pain with quilting and you'll get turned off on quilting.
I use our kitchen island. The height is perfect and the size is more than adequate for even a huge mat. The light is great, too, cause of the drop lights over the island. An added bonus is that I have to clear it off to cut there (it does tend to accumulate stuff.) If you don't have an island, how about the counter? Most are 24" wide, so it's not perfect, but sure beats the floor.