Need to buy rights to use a texture collection

I'm working on some virtual set software and make virtual sets and in the course of doing so I use a lot of textures that I have to make myself because one of the formats we distribute to includes the textures. This is a unique situation because I can't just buy a texture, I need the rights to distribute it.
However, we don't sell a lot of this particular format, so a high cost is not justified.
Does anyone know of or have a diverse collection of architectural textures that I can buy the rights to for a reasonable price?
eric followed by an at and then my company virtualsetworks and then a dot and a com