Hmmm...such fun, Bry.
But I believe the difference in electrical properties of the unequal cables will result in a different LOADING of the driving amplifier, thereby slightly changing the frequwncy response of each side, and THAT's what one could hear. Certainly would be the case with a high output impedence cable running hi-value cables assymmetrically, no?
I find it safer to run asymmetrical interconnects to monos, and then keep the speaker cables equal.
Another thought: imagine coiling the extra cable up and thus creating a huge inductor acting as a high pass into one side!
OTOH the effect is minimal if very low value cables (like Nordost, etc) are used, the output impedence of the amp is very low, and the ratio of L and R sides is small.
Good night.