Version 0.10.3 of zypper will include a bash completion script written by Marek Stopka during Hack Week 2. The script uses zypper help [command] output to retrieve the list of commands and command options in order to feed it to the command line. Given the growing number of zypper's commands and options i believe this will be a pleasant help for many users.
Thanx to Marek for doing this!
Currently the script provides completion of commands and command options. This can be extended in the future to include package name completion for the install, remove and info commands, or even repository aliases for the repo handling commands and the --repo option.