Not sure how relevant this will be, as the door I tackled was different, but here goes:
We had a (former) external front door that was warped - as far as I can remember, one bottom corner was out by half an inch or more. A porch had been added to the house a few years before we bought it, so the door had actually become an internal fromt door (made it easier to remove it for a few days at a time). The door was a simple construction - two side "strips" (sorry, don't have the correct terminology) about 100mm wide, a top strip about 100mm wide, a bottom strip about 150mm wide, and a horizontal strip midway about 150mm wide . There was a panel of reinforced (wired) glass above and below the middle strip.
I removed the glass panels and cut out the middle strip, as we wanted a door with just a single large glass pane. Without the glass and middle strip for additional rigidity, the door moved further out of true. I put a block of wood in the top corner of the door frame (tried a few sizes, ending up with a piece at least twice as thick as the amount by which the bottom of the door was out of true), closed the door on it, and clamped the bottom of the door into the closed position - this was only feasible because the door was now only an empty frame, so running clamps through it was easy (and also we could still use the doorway by walking through the empty frame - being small has its advantages
). When I removed the clamps, the door was almost true, but it took only a few days to resort back to its previous state.
Reckoning that I had nothing to lose, as it would be hard to make the door more unusable, I removed it from the hinges and stripped away all of the paint. Initially I used NitroMors to remove the paint - it took a lot of NitroMors, as there was 20 years worth of paint on it, and even then it left behind yet more paint. Even using it outdoors I had enough of the fumes from the NitroMors, so I attacked the door with a hand plane. Eventually I manged to remove all of the paint and was left with bare wood (pine). I lay the frame on the ground outside, raised up by bricks on all but the warped corner, put a thick layer of wet newspapers on the warped part of the frame, used other heavy objects to apply weight on the warped section, and left for several days. Each evening I would pour more water on the newspapers (this was during a dry spell of the summer so the paers were slowly drying out during the day). This worked surprisingly well. When the wood dried, I sanded it, fitted a pane of laminated glass (6.4mm thick, which helps give the frame some more rigidity I guess), and painted it , and over a year later it is still true.
Some of the above steps may not be practical with your door, but any approach that involved applying dampess to the bare wood for a few days, while applying pressure against the warping, might work for you.
