Fault Tolerance & Master-master-Replication Solution needed

Hi,

I am searching for a Fault Tolerance & Master-master-Replication
Solution which fulfills these requirements

Req1) Master master replication supported, not only master / slave
replication with only the master being
writable. If you do have multiple slave systems they are only useful
from a backup and standby perspective.
Ad Mo must have a db-connection it can write to.
Req2) A plan is needed for deploying changes on the database structure.
What needs to be done to apply a
change saved into a live db environment?
Req3) Not only a warm-standby-solution is needed which is not scalable.
Load Balancing is wanted for the
future.

Do you have experience with Cybercluster or Continuent uni/cluster?
Sounds very promising.

best regards
Ragnar