You can create drop down menus in most apps eg search or a custom one.  This can be achieved creating the following path:

/opt/splunk/etc/apps/<app_name>/local/data/ui/nav

Then created the file default.xml.  An example of the content is:

<nav search_view="search" color="#002B48">
 <view name="search" default='true' />
 <collection label="Dashboards">
 <collection label="Business Intelligence">
 <view name="betting_stats" />
 </collection>
 <collection label="Native Mobile Intelligence">
 <view name="crittercism_overview" />
 <view name="crittercism_trends" />
 </collection>
 <collection label="Operational Intelligence">
 <view name="operational_intelligence" />
 </collection>
 <collection label="Social Media Posture">
 <view name="social_media_posture" />
 </collection>
 </collection>
</nav>

The second line is the view that is loaded.  This can be a dashboard or as above, I've just used the default search view.  Below that are each option in the menu separated by the "<collection>" tags.
Each view name is the name of the dashboard to open.