I have a couple of rolls of 5 lb. and 10 lb. 3M "Scotch Fasteners" that I got from different Home Depots around Houston.
http://www.homedepot.com/p/Scotch-1-...5740/204465388
They both come in longer lengths too.
They are stocked with the picture hooks in the Fastener section, next to the Velcro brand products.