I had this problem, because I changed the firmware to CyanogenMod and did not want to change back.
As I could not find any program to do this (only this or similar threads), I wrote small "program" (targetted for my self) to extract contacts (VCard data) from SBU file. It actually does not extract the file just finds VCard start and end tags, and writes VCard items into file (or files). This generated VCard-file can be used to import contacts to phone.
I only needed the contacts, so this "program" is not capable extracting anything else. It should not be hard trick to extract the file as it seems to be somekind of uncompressed archive file with UTF-16 encoding.
To execute the program you need Java JDK as the attached package contains only the source file. Detailled compile and execution instructions inside the file.
Hopefully this helps someone.