I'm not sure why you would want to go to that much effort.
As far as I know virtually all DVD Players will play a NTSC spec DVD without any problems what so ever.
(I've actually seen a few PAL DVDs where the trailers and bonus material is encoded in NTSC.)
The only thing that usually prevents a NTSC DVD playing on a PAL DVD Player is the region code which you'll remove as you rip the DVD.
If a NTSC DVD plays in black and white there is usually an option in the settings to allow you to select NTSC and regain the colour.
I know the Sony PS2 plays in b/w (unchipped without multi-region software) on a TV but if you feed the signal through a scart lead/modern video you should also get colour without needing to rescale and re-encode the film in PAL.
I expect you will lose alot of quality re-encoding and I wouldn't be surprised if you end up with audio sync problems as well.
I have quite a few NTSC films which I can watch quite happily on a PAL TV...