KogasAngel is a wonderful angsty author and she's done quite few centering around Sesshomaru's betrayal
Here's her Spark Archive:
dokuga.com/spark/profile?&aid=1103
And her Dokuga Profile:
dokuga.com/component/comprofiler/viewprofile?user=5347
*the profile will lead you to her fanfictions.
Gotta warn you though, she writes a lot of MA material, so if you are a YIM make sure you double check the ratings! Wouldn't want to corrupt our Young Impressionable Marbles.
Good luck on you hunt and if you find anything you really like, dont forget to recommind! I'll be checking out some of the ones you listed
I love those super angsty stories too.
oh and shamelessly plugging my own story The Bridal Creed.
www.dokuga.com/fanfiction/story/3601/1 Its pretty mild right now, but it will eventually be super angsty with misunderstandings, assumed betrayal, etc. Like I said its just kinda taking off (even though its at chapter 10 - I'm currently outlining chapter 11... i'm a little slow with getting this weeks update out) so ther isn't any of that kind of angst yet - although there IS angst in it. If you decide to read, be sure to send suggestions or tips on how I can improve. <3
EDIT: Also, Oroyukae is another great angsty writer, though less about Sesshomaru betrayal. Just heavily angsty:
dokuga.com/component/comprofiler/viewprofile?user=1969