I don't believe there is any way to change that information without also changing it in the source. Even if you do find a way to update the strings by manually changing data in the SQL database, the next time the ABS Regen process runs and see any changes in the AD objects it may very well resynchronize the original displayName value back into the SQL database, overwriting your change.
The only way to accomplish this on a one-by-one basis would be to create Outlook contacts and then alter the Full Name field to appear as you want it, but that would be a poor solution for environemnts with more than a handful (<10) of users.
Jeff Schertz, PointBridge | MVP | MCITP: Enterprise Messaging | MCTS: OCS