Is it possible to have multiple locales that use different domains instead of subfolders?
It is discussed here in the craft docs: 

There is an example with different toplevel domains.

English and German each get their own domain

craft/
public_html/            --&gt; example.com/
    .htaccess
    index.php
public_de/              --&gt; example.de/
    .htaccess
    index.php