I do all my quilting on a Janome 6600 - including this one
http://www.quiltingboard.com/t-62514-1.htm
which is 96 ins square.
I dont have a big fancy sewing room, its very small, but have a table behind the Janome (set-in) table, and to the left hand side, to support the weight of the quilt while working.
I do all my fmq freehand, no marking. This is the biggest I've done but have done two large double bed size as well.
I dont roll the quilt, just "puddle" around the machine bed - work from the middle out to each corner then turn 45 degrees and work again out to next corner.