hi,
first i have serious soldering skills and access to a SMT/BGA rework station.
and im not afraid of breaking some ipods, but is it technically possible to dump the vulnerable bootrom, flash it und solder it back in a late09 ipod or updated 3gs? or what is the difference between MB and MC 8gb ipod touch?

it is not on a separate chip unfortunately, it's actually _within_ the s5l, so you can't dump it via hardware.