I know that this is and example module only meant to demonstrate and help developers. But I tried working with it and found that it is not working properly. On fresh installation of drupal 7 the authcache_example module does not work for few reasons including:
1. Install file uses old d6 schema implementation techniques.
2. The use of db functions not longer supported such as db_result
3. Breaks on save and/or submit
In addition to that the module lacked:
1. Drupal code standards
2. Access issues are not handled properly.
I worked on the module to convert it to proper D7 module file. I am positive it needs more work, but at least I was able to clean it a little and get it to function on a fresh D7 install. Please see patch and review it. If it passes your review and wish to commit it to the working tree, I would appreciate if you attribute the commit to me.