An MD83 First Officer encountered wake vortex from a preceding A320 on takeoff from LAS that produced a powerful roll that took full control deflection to counter. The reporter cited ATC procedure in not providing enough in-trail spacing; although it is not clear why the clearance was not refused.

Narrative

[At LAS] we were in an MD83 and cleared to take off behind an Airbus 320. They had just initiated their takeoff rotation and we were cleared for takeoff while already in position. There was no wind and clear skies. As soon as we passed 500 FT AGL the controls started to fight me in a roll situation. I figured it was the wake of the Airbus and corrected while climbing. As we climbed it became more and more pronounced until at 2;000 FT AGL I had completely run out of aileron controls (full stops on the yoke to the right) and was quickly running out of right rudder. The plane continued to roll. I seriously thought we were going to roll over; and then we finally broke free and told Tower we were turning off the SID due to wake turbulence.The problem lies in forcing a plane to take off immediately after another has rotated and forced to follow a specific path identical to that plane. We were also forced to comply with 220 KTS on the departure - thus also forcing greater wake turbulence (heavy; clean and slow). We were left with no options to break free from the wake of the prior aircraft. I've also had wake turbulence problems with a variety of other aircraft (albeit not so severe) on this same departure. After 6 miles of separation you are cleared for the exact same departure. This just isn't enough room to avoid wake turbulence.