I would just create a new style in the style sheet for featured products (example NewDialogTitle) and have it reference that class instead by editing the dialog.tpl and in this line:
Code:
<TD height=15 class=DialogTitle background="{$ImagesDir}/dialog_bg_n.gif" valign=bottom>{$title}</TD>
Edit it to have something like:
Code:
<TD height=15 {if $title eq $lng.lbl_featured_products } class=NewDialogTitle {else} class=DialogTitle {/if} background="{$ImagesDir}/dialog_bg_n.gif" valign=bottom>{$title}</TD>
This is NOT tested, so I'm not sure if it will work, but it should be a start and keep you from hard coding anything.
Backup first!
Carrie