FWIW, there are quite a few Audio Hi-End dealers that do just that...Stereophile magazine is full of 'em. Unfortunately, interconnects have RCA's or XLR's and speaker cables are (when terminated) equipped with either lugs (spades), bananas, or pins, not 1/4 phone plugs or SpeakOns. Obviously, this is useless to a guitarist/bassist. When you're talking cables that cost as much as a bike, an in-home no-obligation demo is certainly de rigeur.
I'm wondering if Lava could do just that....sort of a put your money where your mouth is demo deal. Considering he's a one man shop, that's probably undooable.
It's hard to convince audiophiles to spend big-bucks on cables, nevermind musicians.