2.6.25 suspends correctly on my T61 using
# echo mem >/sys/power/state

(though the patch that started this thread broke it, it works again when reverted)

I use the attached .config -- perhaps you can send me your .config
and I can try it on this end in case there is some config issue?
(The T61 happens to be the only machine I have with me on this trip)

My T61 has intel video, which X restores when in graphics mode.
However, in older kernels I needed to manually switch virtual consoles
on resume to coax X to do this)
With 2.6.25's i915 driver, video restores even w/o X running.

The T61p has add-in graphics, so Documentation/power/video.txt
workarounds may be necessary -- depending on what grahics device,
bios and graphics driver are running.

-Len