[IDEA] Highlight messages by sender in Mail interfaces

One thing I've wished was a reality for Mail applications is to highlight all messages by a certain sender. I know everyone sorts and groups their emails differently, but I would think that sorting messages by Date is one of the most common.
Sure, some people sort by title, some by Read or Unread status, but by far the most common use case I've seen is to sort by date, so you know you're seeing the most recently sent.

However, many times I'll need to find a message by that sender. For instance, if Brian Chan emails me about developing a new interface for something on Tuesday, and on Thursday, writes another email asking if I got the first email.

This new email is out of the scope of a "thread" of emails, so grouping my messages by thread doesn't really help. Also, while I can sort by Sender, it can be cumbersome to find the right block of emails, especially if there is a lot.
I would go so far as to say that sorting by Sender is more often a hassle than it is a help.

So the solution I've come up with is that when you select a message, all messages from that sender will be automatically highlighted. This way, I can select the one I am reading, then scroll down in my pane, and see the most recent emails Brian has sent me.

Here is an example of what I am talking about (click for a larger version of the image):
Email UI Idea

I am sure that this is actually pretty simple to do in a Thunderbird plugin, but it would be nice if all mail interfaces adopted this thinking.

Or perhaps it's an edge case. What do you think?