Right front brake dragging

I have a 2001 GA with a brake problem. The right front brake isn't releasing and is a constistantly dragging on the rotor and gets worse as the brake heats up. The car was a recent purchase and after seeing that the right front pad was worn completely down compared to about 3/4 of the pad remaining on the left side, I figured that problem was the caliper and replaced it. It didn't go away. I have tried disconnecting the ABS by pulling out the fuse and I've even disconnected the vacuum from the brake booster with no effect. The car has been shaking at highway speed due to the rotor warping under the heat. I swapped the right and left rotor to see if the problem would follow the rotor and it didn't... but the shaking and vibrations are gone for the moment.
Could the problem be the master cylinder? or should I be looking elsewhere? The previous owner said the car had some (repaired) body damage when it was put into a ditch a year back, an I haven't throughly checked the brake lines.. but could a damaged line hold a constant pressure like that?
Any help would be appreciated, I've been working on this for over two months.

A collapsed brake line will most definatly do that. I will look good on the outside,but it's on the inside that counts. This happens when people use vise grips to pinch off the line instead of the proper tool. My advise would be to replace the brake line (the rubber one). Hope this helps...Mike...

I had the same trouble with mine not even a year ago and months before that too. The piston in the caliper got stick and wouldnt depress unless you did it manually. Costed me a set of rotors and a few sets of pads. I had to clean the entire calipers and massage the piston in and out till it moved on its own. The pistons work good now and my pads are lasting and wearing evenly now. I dont know if that helps.

I agree with surgicaltech. He said that he replaced the caliper already, so it couldn't be the piston. A budy of mine said that he did that to his Suzuki once. Took him a couple of months to figure it out too. He ended up replacing the rubber hoses with steel ones anyways, and it went away.