Thanks for the suggestions all! I have tried resetting the SMC and all that - the previous owner apparently had some electrical issues at their home, which is what killed off the USB ports and ultimately led them to ditch the tower. I have several other Macs that I plan on using to install OS X on; I was going to use my 2010 Pro to install OS X on a HDD, patch it for the 1,1, then stick the drive in the old one, so I'm not so worried about getting OS X installed. I don't need anything fancy with a USB card - a USB 2 card would work just fine.
I'm still debating getting it up and running or just parting it out; the only bits in there that are probably worth anything are the memory risers and maybe the GPU, so I'm not sure that it's actually worth it to part it out.
I'm thinking at this point about fixing it up and giving it to my dad - he has a 2009 mini that he finds to be lagging a bit for him. Throw 16GB of RAM in the Pro from eBay for $20, pop in an SSD that I have around, and it should make a good machine for him for a good while to come. All I'd need to buy is the RAM and a cheap USB card. Any suggestions on a basic 4-5 port USB 2 card?
The machine has an ATI Radeon X1900 XT 512MB in it at the moment.
Also,
this is the correct RAM for this machine, yes?