To get your truecolor modes on the Radeon you just need to open P96Mode and toggle the color depth gadget on your truecolor modes to Truecolor+Alpha.
Regarding Radeon 9200 being slow, there seems to be a bug in P96mode when you change graphics cards it sometimes converts to nonsensical refresh rates and/or pixel depth modes, sometimes this makes modes run really slow or causes crashes even though initially it seems like it is working. Best option is to just recreate the modes, which is really easy with the Radeon on DVI since you pretty much just put in 60Hz vertical and most of the time it will work with minor tweaking.
I have the true color+Alpha on my modes. Before on voodoo 5 I had 4 options. On Radeon its only chunky, hi color and true color+alpha.
As far as resolutions go I plan to try and see if I can get more working by creating new ones from scratch. Its acting strange from this copy of the old ones like you said. Still looks great on DVI though. It does appear that the vertical is the issue on the resolutions that dont work. How do you edit that on a new resolution. Its not a field it lets me change from what I have tried?
EDIT:
I got it, I just had to move the slider in the pixel clock is all. All my resolutions are back as well after I recreated them all.