AIX's LFS, IRIX's XFS, Digital Unix's AdvFS. These are pretty fast and stable.
WinNT's NTFS is supposed to be log-structured too and reasonably stable (don't
know about speed, but making anything fast within WinNT is not easy).
SunOS's ufs has also been hacked by adding a log to it. I don't know if it's
fast and/or stable, though.
Of course, there's also BSD's LFS, but I don't know if it's stable in any
current BSD derivative.
I'm sure there are others,
Stefan