Besides people in PAL countries, you have to take into account people that use downloaded footage that was downscaled and/or people that are using blue ray disc rips with a heigth of 720 or 1080 lines.

Also, there are people that prefer to resize to a resultion that works with a 1.0 PAR, rather than editing 720x480 or 720x576 with flagged PAR.
Besides, I do watch my vids on a 22" 16:10 screen, so I know what you mean... it would be better.
Anyways...what would be the point of making a 848x480 if everyone besides you would be sending over 4:3 vids? Pointless. Upscaling and cropping everyone's track but yours? I think that the best quality in such case would be making it 640x480 and letterboxing or cropping the sides to yours. Like I said, you have to take in account that you have no way to know what resolution most vids will be in.
And yeah, about the 768x432 vs 848x480 in case of more widescreen sources... I guess it's a matter of preferences. The area difference between 768x432 and 848x480 isn't that big anyway... I guess that if most people would be sending 720x480 vids with 16:9 flag, than the smartest thing to do would be making the vid a 720x480 with 16:9 flag.
Or if most sources were to be 720p, the HD release would be win. So yeah, the actual resolution is still a thing that needs to be decided every round, imho.
