You can display a merchant list programmatically. You just need to add some code to your Views as well as your theme.
I've written how to display a merchant list in the form of a drop down (<select>) list as well as an HTML (<ul>) list here: http://www.datafeedr.com/forums/showthread.php?t=6778
To remove the Tags field from the Advanced Search widget, go here: The Factory > Your Store > VIEWS > WIDGETS > Advanced Search > Text module > Click template icon (
Then remove this line:
<label for="tags">Tags</label> [search.tags]