Starting a thread to discuss ESXi on Mac Pro hardware.
MacPro1,1
MacPro2,1
The first two generation Mac Pro's boot to black screen prompting to pick cd boot type 1 or 2. However no keyboard input is accepted. I suspect this may be solvable with some hacking.
MacPro3,1
MacPro4,1
MacPro5,1
The three most recent generation Mac Pro's install fine to standard sata drives.
I beleive that none of apple's hardware raid cards are workable for booting from. The most common fiber channel cards apple shiped with Mac Pro's from LSI also do not work. The Xraid still works if you connect it to a supported FC adapter however.
If you have other Mac + ESXi questions start your own thread 
Let's keep this one specific to installing ESXi 5.0 on Mac Pro hardware..
Blake