Hmmm, they couldn't find where the oil was burning at eh?
Well, go back and tell them that unless they took apart the engine, and inspected the pistons and their rings, no shit they wouldn't find why it was burning oil.
Fuck Toyota, have your parents yell at them, especially if you are still under warranty. If you don't get this fixed, it's only going to get worse, and then next thing you know, your engine is blown, your warranty is up, and you are shit outta luck.
If they are still reluctant to fix it, just blow the engine yourself. Fuck them.
Oh, and as for 1 quart per 1000 miles, tell them that's bullshit, and you would like to see that in writing somewhere. 1 quart per 1000 miles is what a car with busted piston rings on all 4 cylinders would burn.
Oh, and on a side note, I change my oil every 5,000 miles, I have a 2000 GTS manual, and I'm not burning any oil (actually, it's impossible for any car not to burn any oil at all, but you know what I mean.