How can I change a rendered user display to a combination of fields linking to the user? I have a set of users on the site I'm building that have First and Last name fields in their profile.  How can I create a display that will show the user link as "Last name value, First name value" all inline?

There are a number of places where this is how I want user references to show up.  In some other places, it would be ideal to show those fields, and a couple of others along with the user's image.  Then of course there is the full profile view.  I had though this must be done with different display types, but can not see anyway to bring fields inline with each other, or adjust what text makes up the link.
One option would be to use:
Real Name

The RealName module allows the administrator to choose fields from the
user profile that will be used to add a &quot;real name&quot; element (method)
to a user object. Hook_user is used to automatically add this to any
user object that is loaded. It will also optionally set all nodes and
comments to show this name.

For Example:


By default only the raw username is being shown, as you can see at the
top of the page.

Change this to:

Result:

source: Change Drupal Usernames with the Real Name Module