After installing coreutils-8.12 on OSX 10.7 today, I found an issue immediately where df was overflowing the structure returned from statvfs.  On OSX 10.7 the relevant fields of the statvfs structure are defined to be fsblkcnt_t, or only 4 bytes long.  I have put together an initial fix for 10.7.  Hope this helps.

Looking through your bug reports, I believe this is likely a fix for bug 7355.

-Herb