It is possible. I think in practice it depends on your provider. Mine is extremely reluctant. I have had to choose alternative options.
Assuming you would you want to share the same users, you could probably do everything from one domain, thus one db. Would be faster too.
I'm working on an iPhone solution in a similar direction. I need two separate GUI's fronting the same DB. I use the HTTP USER AGENT to send the visitor to one place or another. You could use something like this in the beginning of your index.php:
PHP:
<?php
// Declare referring url as variable
$referrer = $_SERVER['HTTP_REFERER'];
// Conditionally select the domain you want to fork from
if ($referrer == "http://Mysite1extra.com"){
// Do something
}
else{
// Do something else
}
?>
Nest the statements depending on the number of virtual domains you have pointing to the physical.
You could simply create a completely new template and set the D_TEMP accordingly. Alternatively, if you will have more, major differences, you could copy to a sub-domain, and redirect using something like the above.
Hope this is some food for thought for you.
Cheers!
