Now coming back to an older thread:
http://www.macosx.com/forums/showthread.php?t=36142
How about resizing Mac OS X HFS+ partitions - is it possible?
Does anybody have experience doing this with FWB Partition Toolkit (which is, as far as I understand, Max OS 8/9 only but capable to handle HFS+, see
http://www.fwb.com/html/partition_toolkit.html)?
How about hdiutil, can it be used for this purpose (see
http://www.osxfaq.com/man/1/hdiutil.ws)?
Or are there other recommendable tools?