They have a bootable CD based on HFS file system. I made an iso of this CD and have used the usual lines in menu.lst to boot this .iso
Although this is not the most adecuate section of the forum for this topic...
That CD comes not only for MACs, but also as an ISO download, so you don't need to make a new ISO. Just download the ISO from their site.
Since Grub4Dos does not support HFS at this time,
perhaps there is an intermediate step(s) like a bootloader to call up first that then points to this .iso
Your problem is not so much HFS(plus), but (U)EFI. The "rEFIT" tool is NOT for BIOS-based systems
rEFIt is a boot menu and maintenance toolkit for EFI-based machines like the Intel Macs.
That means, at least in theory, (U)EFI
and no need of a special bootloader.
no luck yet. I'm doing this in Virtual Box but also have burn a CD to test directly on a mac.
In addition, from http://en.wikipedia.org/wiki/Extensible_Firmware_Interface#Boot_manager
Boot manager: An EFI boot manager is also used to select and load the operating system, removing the need for a dedicated boot loader mechanism (the OS boot loader is an EFI application).
Linux has been able to use EFI at boot time since early 2000, using the elilo EFI boot loader or, more recently, EFI versions of GRUB.
Apple uses EFI for its line of Intel-based Macs. Mac OS X v10.4 Tiger for Intel and Mac OS X v10.5 Leopard support EFI v1.10 in 32-bit mode, even on 64-bit CPUs (newer Macs have 64-bit EFI).
elilo is likely to be the standard bootloader on any version of Linux running on Intel-based Apple Macintosh hardware
GRUB version for EFI: http://packages.debian.org/sid/grub-efi