Display Android Thread ID in LogCat
Run ADb in the command shell like this:
C:\Temp>adb logcat -v threadtime > t.txt
This will run in parallel to your Eclipse session. Once you done with Eclipse, Ctrl+C from shell and you'll have the log in t.txt. It is not as nice as having it in the Eclipse logcat window but will do the job.
Answering myself: Since 2 weeks have gone by and no concrete suggestion as to how to add a a 6th column for thread id in LogCat has been provided, I can only assume that this isn't possible (currently).