The only reason I can figure for the multiple Cat 5 wiring is redundancy. It's much simpler to simply switch to another cable in case of failure than to have to run another line later...
Looks like James is gone, I'll add this for anyone else looking at the projector issue. I had one that a power outage damaged. When the power went out and didn't come on for several minutes, the heat that was being removed by the fan just sat inside and cooked the LCD panels and polarizer.
It started showing up shortly after as a large ugly blot in the middle of the screen. I can't say that I know if all pj's are at risk for something like this, but I got a UPS after that, and plugged the pj into that, running a cord across the ceiling tile and down to the projector.
A UPC? Is that a uninterrupted power conditioner or something? If it's a wall wart, it's not uninterrupted, perhaps I misunderstand you.
What I described above looks like a large power bar/surge supressor. It has an actual battery built in that stays charged, and in the even of a power outage, the battery circuit provides 120v so a projector can stay running and it's fan keeps removing the heat. You can safely shut off the projector until power comes back on to the other components and you can resume your movie.
I also have a wall wart style surge suppressor for the treadmill. A great idea for surge suppression and it works just fine, but it can't provide any power to a projector should the power fail. In that case, the projector would immediately shut off, and the bulb heat inside does not get removed.
Sorry for the long explanation! So my UPS(uninterrupted power supply) unit sits out of site, and I ran an extension from it up into the ceiling over to my projector so it's protected from power failure and power surges too. Hopefully others can chime in although it seems Audiogon has few members with home theaters.