When I got upstairs, he also mentioned that he was going to need to borrow a keyboard and mouse so he could get past the serial number prompt to the point where he could configure his Mac to talk to his Bluetooth wireless keyboard and mouse. Rather than go through the potential hassle and drama of seeing such items from our internal support folks, we came downstairs and grabbed a set from my old iMac. (There's only a serial number prompt for the Mac OS X Server installation, and Tom got the server OS instead of the plain desktop OS, so he could play with it.)
The machine did, indeed, fail to power up. I checked all of the connections, which appeared to be solid, before deciding a peek inside would be a good idea.
I've seen photos, and been near plastic-shielded machines with the metal side off, but this was my first time actually inside a G5. It's nice and roomy, and very nicely laid out. It was fairly quickly clear that the NVIDIA graphics card wasn't seated properly, so I pushed it back into place. Must've been jostled loose in transit. Hit the power button again, and the machine came up happily. Tom got through the initial setup, paired his keyboard and mouse to the Mac's Bluetooth feature, and let me get on my way.
Oh... and the 30" Cinema Display is even more impressive on a desk than it was surrounded by a crowd of people pawing over it on the day it was announced!