Frankly, I know of no shop near me that carries them and I've not seen them myself. Most larger gun stores will stock VXII and VXIII lines and the big box stores will carry the Rifleman and VXI stuff, but the VX-R stuff is (much like the Leupold Ultralights) a bit of a niche product for most storefronts to stock in earnest....
I usually use the Sightron SII 1.5x-6x/42 or a Bushnell Elite 3200 1.5x-5x on my ARs with magnified optics, although I have recently used a couple of the Leupold VXII 1x-4x optics. I did mount the Burris 2x-7x FFII on a couple of 6.8SPC builds, but I do not like the fact that I cannot use flip-up lens covers with the FFII.