I think I figured it out. But, if you follow my instructions, you do it at your own risk, as always 
There is a whole set of problems, one leading into another, which brakes Kmail after OpenSUSE 11.4 upgraded to 12.1.
I suspect that this scenario is a rolling issue between upgrades on different distro’s that ship KDE.
So, from the top: Kmail dies. Digging dipper shows that Akonadi does not start properly. Digging dipper, Akonadi uses MySql as default internal storage. Thus, MySQL is a culprit. Further, there is more than one thing wrong with MySQL!
1st: make sure MySql starts with KDE. YaST -> System -> System services. Here, make sure MySQL is running (probably not) and go to expert mode and select MySQL to start for runlevel 5 ( I also selected 3, but probably for no good reason).
2nd: it looks like Akonadi failed to create its default database during its post-install config because… yup, MySQl was not running. I think that reinstalling Akonadi with running MySQL may solve problem from here.
Now, how I got Akonadi fixed in a quick and dirty way. I do not claim any profound understanding of this arcane art, it was merely intuition + Google.
in here, http://userbase.kde.org/Akonadi_4.4/Troubleshooting in the section “Kubuntu 10.04 (Lucid Lynx) Upgrade” I found some obscure spells, which suggest the same scenario, Akonadi is missing its default database. The instructions are for Ubuntu (a-hem), and they will not work in OpenSUSE due to more rigid restrictions for sudo. Some commands must be ran from root account. replace** user_name** with your desktop login name.
This method will most likely destroy some or all local content you had in Kmail, and contacts too. I didn’t care since I rely on IMAP and LDAP.
remove Akonadi config folder:
> rm -r /home/user_name/.local/share/akonadi
run Akonadi to rebuild default config:
> akonadictl starts
get root:
su -
create default db for Akonadi:
mysql_install_db --datadir=/home/user_name/.local/share/akonadi/db_data/
do more magic:
mysql_upgrade --socket=/home/user_name/.local/share/akonadi/db_misc/mysql.socket
if you got no errors at this point, it is possible I actually know what I am are doing
leave root:
exit
restart Akonadi:
> akonadictl stop
> akonadictl start
from this point I was able to start Kmail and restore my accounts by hand.
NB: it is reasonable to make sure that Akonadi (I have no clue where or what it is, but Alt+F2, type akonadi and select Akonadi Configuration, gets it) uses on Akonadi Server Configuration tab ‘Use Internal MySQL’ is checked and path to executable has ‘/usr/sbin/mysqld’.
good luck