How Would You Create a Copyable Contact List?

I need to create a copyable contact list… so I have a data store like this:

ds_contacts
   first_name
   last_name
   email

And I want to create a single variable called email_list from the content of ds_contacts who’s value looks like this:

Joe Doe - joe@doe.com
Homer Simpson - homer@simpson.com
Fred Smith - fred@smith.com

So I can then let the user assign the value of email_list to their paste buffer and use elsewhere.

How would you go about assigning the value of email_list?