In case it's any help, this photo from @jrd617 is pretty great comparison shot for a number of brown herringbone fabrics. (From this post: http://www.styleforum.net/t/56404/unfunded-liabilities-a-k-a-the-cloth-thread/9200_50#post_7022265.)
Thanks, this was really helpful. Also, thanks to Clags, Archie and TM79 for their thoughts. I'm down to 26 or 18 and will just need to think about it for a little while as they are fairly different.