Perhaps helium filled balloons?
http://www.roger-russell.com/wire/wire.htm#expensive - it's really the bible on speaker wire as far as I'm concerned. I'm running the suggested outdoor low voltage wire he suggests. Good stuff - 12 gauge and it was free, left over from some outdoor lighting I ripped out.
Of course if you've done a real blind A-B test - and someone heard a difference.. I'm all ears..