A new project at NIST, Computer Forensic Reference Data Sets (CFReDS, 
http://www.cfreds.nist.gov/), has posted a few hard drive images for 
investigators and academics to work with. Among these is an image of 
a Mac filesystem that is available in Encase, iLook, and dd formats. 
It's like a rosetta stone for anybody trying to evaluate and process 
these forensic file formats!