Smartfolders- Can I narrow the query?
Ok, there’s a way to “hack” into SmartFolders and change the locations. 

Rules: 


You can’t do it from the UI
It involves having the smart folder saved
I wrote it in spanish a long time ago in a blog post (spanish)


For the sake of helping you (I’m assuming you don’t speak spanish), I’ll transcribe the relevant information here. 

Please note that the blog explains how to add more than one location to the search, not how to exclude (something I don’t believe is possible).

So, the short version: 


Save your smart folder, the search location is really not important (we’re going to change it!) but make sure you use the searching “terms” that you want. Name it something like: IHATESMARTFOLDERS. Ok, you can name it differently if ya wish ;)
Go to your ~/Library/Saved Searches and you should see your saved smart folder. 
Once you have located your smart Folder, you have to open it with a text editor like TextWrangler (or anything that can save Plain Text). Do not use Pages…
Once you have it in your favorite editor, go to the end. You’ll see something like this: 



&lt;key&gt;FXScopeArrayOfPaths&lt;/key&gt;
&lt;array&gt;
           &lt;string&gt;/Users/martin/Desktop&lt;/string&gt;
&lt;/array&gt;



Note My smart folder was created for searching on my Desktop.

Good. As you can see the path is in an Array. If you know something about arrays, you’ll know that they are a collection of items. This means we can go ahead and add more items to this particular collection:

For example: 

&lt;key&gt;FXScopeArrayOfPaths&lt;/key&gt;
&lt;array&gt;
         &lt;string&gt;/Users/martin/Desktop&lt;/string&gt;
         &lt;string&gt;/Users/martin/Pictures/MacStuff&lt;/string&gt;
         &lt;string&gt;/Users/martin/Pictures/Me&lt;/string&gt;
&lt;/array&gt;


I have added two more folders to my smart -not so smart- folder. 

Now in order for this to start working you have to: 


Save the smart folder (remember to use plain text!)
Restart Finder. 


And voilà. 

Sadly, I haven’t found a way to exclude a location.