Local would be your best bet. The 'online' suppliers are good for small quantities, if you're in an area that doesn't have a retailer that will sell cut to size, but on full sticks (especially one as pricey as that one will be), the local supplier will usually have a better price.
I don't know where you are, but I can easily get that in 12' lengths, and one of my distributor's shows that available in 20' as well, though I don't know if that would come out of the SE location, or would have to come down from the Northeast (and have a longer lead time).
Dawson