As Robin says, most people would go for OS X Server, because it has tools specifically built to do just this, providing you bind the clients to LDAP.
Aside from that, OS X is designed hierarchically. You could try just adding the desired .plist files in /Library/Preferences instead of ~/Library/Preferences and then deleting said files, if they already exist, from ~/Library/Preferences (since files in ~/Library generally override those in /Library )
There is also the default "User Template" hiding in the System Folder, from which all new users' home folders are created. You could edit this, but the change would only affect accounts created after the imaged machines have their first boot.