i don't know about special shielded wires for speakers, i think it is a marketing gimmick for speaker wire to begin with - audio signal is normally maxed out at 20000 Hz (human limit), and most wires can handle 20 kHz... the special design is needed for super high frequencies, we don't worry about them here... gauge is needed to pass amperage... so? you can get any shielded wire (coax Sat cable will be fine, it can pass upto a THz)? it is not convenient to work with though...

How do you power your system? are the power wires shielded?