Haha! I knew this would be coming eventually. Well done, lads! Planning support for anything other than 7,3? 11,2, perhaps? 
)
According to the Apple Museum site these are the PowerMac G5 revisions:
PowerMac7,2 Power Macintosh G5, Power Macintosh G5 (Early 2005, dual 2.0 + 2.3 GHz)
PowerMac7,3 Power Macintosh G5 (June 2004), Power Macintosh G5 (Early 2005, dual 2.7 GHz)
PowerMac9,1 Power Macintosh G5 (Late 2004)
PowerMac11,2 Power Macintosh G5 (Late 2005)
There was also a PowerMac12,1 which was an iMac G5
and an earlier PowerMac8,1 and 8,2 which were also Imac G5's.
source:
http://www.theapplemuseum.com/index.php?id=36#
