took a while here too, sorry 'bout that

good news is there doesn't seem to be anything wrong with your HW.

bad news is, ain't exactly a HW engineer
i merely compared your file with what happens on my N900 when i slide kbd, switch from 3G to WLAN aso.
all looks perfectly normal to me

i know it is frustrating if you don't have another N900 possibly even another mobile phone, but could you try & made a STOCK standard install (still with your personal data, of course, but WITHOUT any extras-testing, leave alone extras-dev SWs...)
even better, not even extras stuff

my way of saying that it could be SW
also hinted at maybe by the fact that if the device is idle, it doesn't crash.
i assume that even when idle, you have 2G/3G or even WLAN on, right?
slide HW kbd to check if you are still online aso?