I cannot imagine anyone reproducing a 60" sign... It makes no economic sense. 60" signs appeal only to those who have the room to display them. Thats why their prices are fairly reasonable and on the low side. It is simply a matter of supply and demand. The cost to repop a 60" sign would be more than the return... unless you made a VERY RARE one and sold a bunch.
Just my opinion....

------------------
Frank
_________________________
Frank