Half the length, or double the quality?

OK, so I must confess. This was more of a hypothetical question. I was just wondering how much better a speaker cable would have to be if it were twice as long as needed. I have appreciated Erik's questions in the past on non-specific product topics. So, generally speaking, does doubling the needed length (with a better cable) come out to about the same. Keep in mind you can't cut the better cable in half, and therefore have your cake and eat it too.
I'm just trying to "poll" the audience. Sorry for any confusion, and this post may actually make it even more confusing.

Mapleshade believes 8 ft is the ideal length for speaker cables. Some others also believe that shorter is not always better. Of course no agreement. 

Maybe.