I'd recommend that you stop looking specifically for a "FAQ" module and instead look for a highly-customizable blog, forum or articles module.  You can use included customization options to "cut down" one of these more full-featured modules to do the job of a FAQ while offering additional features not commonly found in basic FAQ modules (like "user ratings", "bookmarks", "item submissions" or an "item approval process").  Such modules typically include the ability to create multiple item categories and perform content search.  Best of all, you can use the same module for different tasks based on the options you select.
 

Check out the well-regarded Ventrian NewsArticle module (which is just as easily used as a Blog module) as an example:
 
  http://www.ventrian.com/Products/Modules/NewsArticles.aspx
 
Here's a demo (with search feature):
 
  http://www.ventrian.com/Products/Modules/NewsArticles/DemoBasic.aspx

 
-mamlin