King open conical filter systems are sold everywhere in the automotive aftermarket. While a shielded unit would work better if you take a good look at most of the shields they truely aren't keeping all engine heat out and some look like they probably don't work at all...just looking like it.
If Ken's kit was priced like a heat shield should be included I could see your arguement, but its not. Its priced like a quility adapter and filter can cost, sure it could be done for less but its not out of the range. If it had a effective quility sheild it would cost alot more.
I too have made a pretty slick template for a heat shield for mine. Just didn't follow though on it. Even have all the materials. The LS breaths well under the hood compared to some cars, not that it wouldn't help, just hasn't bugged me enough to take the time to complete it.