I have tried to unwrap a surface and with the following material, however, I have been unable to create a seamless wrap. I tried a couple of different experiments, with placement of the seams at different places on the column, but in all cases, the seam was visible in the final render.
Here are a couple of tries, and the latest one in .blend.
credit for the material - blendswap cf material
cf material.blend (642 KB)