To date I haven't been able to find documented lists of preseeds
anywhere, except for the standard debian installer values given in
You haven't looked hard enough.
Debian's and Ubuntu's example preseed files. I found this preseed option
in forum postings somewhere.
Which preseed option? You might not be able to find the forum posting
but please would you quote this option so we know what you are talking
about?
I can categorically state there is no preseed option for permit-root-login
in Wheezy, Squeeze or Lenny.