You don't need a function for that, you can already do it by using the scroll wheel.  If you see a post by someone you don't like, you keep scrolling down to the next post.

(But I'll admit that it would save me a bit of scrolling. ) 

The problem with trolls is that they are attention whores who can always persuade inexperienced members to answer them. This is were the threads deteriorate, when people actually answer the troll. Trolls thrive from inexperienced users trying to engage in a conversation with them.

 in all honesty what I would like to see is a 'collapse user threads'

So that way instead of an ignore, wich I think would be bad... Just have a 'collapse threads' from such and such users. Possibly bring in a system where you can respond directly to a responce on a thread, and it be in a sub-thread as well, to keep a troll post isolated and further away from sight.

Basically add a button below Add to Friends, and have it 'hide user'. And all that it would do, is remove the posts from that said user. You would still see a two or three line box showing their name, date/time posted, and the ability to un-hide the users posts.

My second idea, would be to add the ability to respond directly to a post, to add a 'tree' type responce system. It would be a pain in the butt, but everything would be easy to follow, would completely remove the need for quotes, and organize the threads so much better. Then people can troll as much as they like, and unless their spamming the entirety of the site, wouldnt be a bother to anyone... and if their spamming the entirety of the site... That should be a 'goodbye' just from the spamming.