I will receive the R52 mainboard Friday, but i think i am going to do it else than i thought.
My current FrankiePad:
R51 mainboard in 14" T40 casing
The defective T42:
no mainboard, 15" SXGA
I think i will swap the R52 board into my FrankiePad (because R52 has DDR2 which is faster and cheaper) because my FrankiePad is my 2nd most used machine (T61 is nr1

)
The T42 won't be used as much, so i will swap the R51 mainboard into the T42.
And about the capabilities of what LCD the mainboard can drive, i found this at the ThinkWiki:
http://www.thinkwiki.org/wiki/Category:R51
One of the following displays:
14.1" TFT display with 1024x768 resolution
15.0" TFT display with 1024x768 resolution
15.0" TFT display with 1400x1050 resolution
http://www.thinkwiki.org/wiki/Category:R52
One of the following displays:
14.1" TFT display with 1024x768 (91 dpi) resolution
15.0" TFT display with 1024x768 (85 dpi) resolution
15.0" TFT display with 1400x1050 (116 dpi) resolution
But i think that the screens i marked bold only can be driven with the ATi GPU.
Can i destroy anything (mainboard / LCD) if i try the combinations?
I want to try if R52 mainboard can drive my T40 14.1" XGA, it probably will
I also want to try if R51 mainboard can drive my T42 15.0" SXGA, not sure about this one