On an internal discussion list, someone mentioned that for a Mac Mini, an external firewire drive was much faster than the internal drive. As I had no firewire, I decided to buy one and try it out. I went with the WD MyBook 500GB drive.
I downloaded SuperDuper to clone my freshly installed internal drive to the external one. It reformatted the default FAT32 partition on the WD and backed everything up. The SuperDuper documentation did warn that not all firewire drives would boot.
I could reboot and press option to load from the external drive. I used a black and white background for the internal and a vibrant flower for the external. But I couldn't get the drive to automatically boot up. Every time I thought I had it, I got the dull black and white.
I figured out that I needed to use System Preferences -> Startup Disk in order to set the boot disk. But all I could see there was the internal and a network boot option. I could see the firewire disk was loaded on the screen. And depending on how I booted it, I could find it in the namespace.
And quite frankly, google failed me here. I didn't find much and what I found did not work.
So I decided to start from scratch and load directly onto the drive. But the installation declared that the firewire drive was not bootable. I reformatted it and then figured out that it had a MBR and not a GUID partitioning scheme. Crap! I fixed that and suddenly I could start installing and booting off of the external drive.