Well you're definitely better off with a long run of balanced XLR vs. single-ended RCA. I'd just go to Guitar Center and grab some Mogami microphone cables. Although I think the Monoprice ones are cheaper.

WHAT?   I spend big $$$ on 3' interconnects and you're advising Monoprice? I'm incensed! (Note to self: pick up more incense.)  Shame, shame!  Actually I do love Monoprice, that's probably the way to go.   I could try to build my own, I still have some PCOCC wire left over from making my speaker wire, but that would make for a very very thick interconnect.  Probably wouldn't be ideal... has anyone tried DIY interconnects using speaker wire?  I don't know  about that technically, would that even work?  Too much resistance?  Or does wire size not matter?

Interconnects tend to range from around 28-18AWG. Going smaller than 28 is typically left for tonearm wire. You can certainly use speaker wire if you want, resistance increases as wire size decreases, so large gauge speaker wire is actually much less resistive than the typical stuff used for interconnects.

Speaker wire normally isn't used though because you'll likely run into termination issues. Most RCA and XLR connectors are not designed to deal with 12 or 14AWG wire. Also, if you're going to do a 30 foot run, you're going to want to have a metal shield, and most speaker wire is not shielded. You could do a four wire star-quad run which has some inherent shielding properties, but that would mean an even larger combined gauge at either end, and there's no way an XLR connector is going to accept 10+AWG wire.

Your best bet is what's already been suggested, shielded Mogami or similar.

The Master 1 looks sweet, but I got this NuForce because it's got 7 inputs and 7 outputs to theoretically in the future use with an Oppo DVD player and add surround without having to put an AVR in the loop.  So far I'm not sure I'm happy with the NuForce though, it seems to be putting a little bit of a hard edge on things, but I'm gonna give it some more time to burn in.

Look here:
http://www.proaudiola.com/XLR-microphone-cables-s/169.htm

They will build you a nice cable to any length (and color) you want with Neutrik ends.

You want the Mogami 2549 or 2534.  The 2534 is quad conductor and better at noise rejection so that might be your better choice here however I can't comment with certainty as I don't know what the RF environment in your place is like have not tried at 30ft run myself.