Why isn't DDS luminance (L8) format supported ?

I am working on an environment where most diffuse are simple shades of gray. I find it sad not to be able to use the DDS luminance only format. My options are : - compress my textures as dxt1, results in poor quality - use the as plain r8g8b8, results in big textures - use Alpha8 and make a custom shader so that it uses Alpha instead of RGB, makes more work

Please add support for Luminance8 format. Cheers