I saw a used Macomber at my LYS.  If you are in the intermountain west and want a BIG Macomber, check out the loom a Three Wishes Fiber Arts in Utah.  She has a wide (I think 48") 16 shaft Macomber in great shape and selling for $4000.  I hung the last 8 shafts on the loom after it was delivered and it worked great.  It has double back beams, on sectional, one plain. 

Deanna