Check out the Wor4 Tacrail

The WOR4 TacRail was conceptualized, designed, and manufactured by David Woroner, President of Survival Consultants International. It is injection molded, cast from aerospace grade 7071 aluminum. (The same material utilized in the newest upper and lower receivers on the Smith and Wesson M4/M16 type rifles.)

Read more about this picatinny tactical railing system.