Any converter I have used has created lag, and I don't use them anymore. Trying to go through a VCR first has also created lag, both were bad. I have played the old wipeouts on lcds before and it has never been good, there always seems to be some lag compared to a tube tv, and it never looks as good as a tube tv. I have some nice tube tvs that play both signals, but it sounds like you want just a LCD. A multiple signal hd tube tv would be perfect for what you want, but I don't know if they even make them. I have an hd tube tv which looks and plays excellent for all the games, but it is only NTSC. I will give my 24" LCD a try and see how it works as I have not tested it yet. It is excellent for the psp, and I haven't seen a better picture for HD.
I didnt find any crts that did all the resolutions . I have Sony wega tvs for my old systems and they look fantastic, but are not hi def. My tube philips hd tv looks grat for Wohd. I am sure that the Sony hd wega widescreen would look great for all, AND play correctly. The only question would be to find a pal/ ntcs model, which had to have been made since my wegas are that.