I already wrote a lot about the CBT bug and how to create a workaround. Also Veeam added support for discovering changed size vmdks so the workaround can be easily applied but all the time the workaround had some side effects on backup performance. So going this way is not a real solution.
Currently the patch is only available for 5.1 versions of vSpher so users of 5.0 or 5.5 are still affected by the bug. But keeping the time in mind VMware needed to find a real solution for this problem could mean it shouldn't be a big step to also patch the other versions.