I added the theme "custom_corners" to Moodle 1.9 because I noticed that many more places/files needed to be changed than I estimated. And there are some "very individual" Moodle pages which show their true face with "custom_corners".
Changes to the description about "round_corners" in MDL-9383:
_ name changed to "custom_corners" to better communicate the possibilities and Roger Johansson's naming: "Transparent custom corners and borders"
_ library "lib/custom_corners_lib.php" added to support consistent implementation in new pages
_ many more files changed than listed