After reviewing the codes, I’m now not sure if my previous post is correct. Both the IRC and UPC specify a 24″ maximum length for a fixture tailpiece into a trap. I believe that I was confusing an exemption in the codes for washing machine standpipes. Nonetheless, what’s good for the goose would seem to be good for the gander. Although the codes do seem to prhibit lav tailpieces > 24″, I’m not sure that llwngths up to 36″-42″ wouldn’t function properly, except of course they would be “against code.” I’d appreciate any comments from my plumbing brethren on this.