Bower64's 450 collection was up for sale on RunRyder not that long ago. Now I wish I had picked up one of his 450's to help him out and have a memento. Here is another ad for his Gazaur 480: http://www.rcgroups.com/forums/showthread.php?t=1780748
BTW: it occurs to me that, aside from size, a big difference between the 500 and 450 is the greater distance from the heli's center of mass to the rotor disk. I can sure see it and feel it during flight. This makes me think that a DFC head would make the 500 noticeably more agile.