NuWa puts those exterior shades on their rigs as an option. You may wish to contact them for a price (800-835-0676). Their parts prices are very competitive.
Also, I don't know what shape your interior shades are in, but we converted last year to MCD Duo Shades. Their interior daytime shade is made of a similar material as what your exterior shade probably is. In our case, the MCD shade eliminated the need for an exterior shade and all the maintenance that goes along with it.
Dave & Jo Ann
'08 HitchHiker Champagne 35LKRSB | '11 F350 Lariat 6.7PSD