Hello!

Here's how I did it:

1. First we need to overwrite getFresh() method of the Illuminate\Database\Query\Builder class. So, I created the following class:

<?php namespace App\Database; // Or use any namespace you think suits you better

use Illuminate\Database\Query\Builder as QueryBuilder;

class LdapQueryBuilder extends QueryBuilder {
	
	public function getFresh($columns = array())
	{
		$users = parent::getFresh($columns);

		foreach($users as &$user)
		{
			// Provide your logic here to fetch data from both sources (DB and LDAP) and add to $user.
			$user->otherField = $otherValue;
		}

		return $users;
	}
}

2. Overwrite Illuminate\Database\Eloquent\Model::newBaseQueryBuilder() in your model so we can use our custom query builder:

<?php namespace App\Models;

use ...; // Your use statements.
use App\Database\LdapQueryBuilder;

class User extends ... implements ... { // Your extends and implements statements.

	...

	protected function newBaseQueryBuilder()
	{
		$conn = $this->getConnection();

		$grammar = $conn->getQueryGrammar();

		return new LdapQueryBuilder($conn, $grammar, $conn->getPostProcessor());
	}

}

Now, everytime your model returns any result (including in Auth::user()), your returned model will contain attributes from LDAP and from DB, according the logic implemented in your custom query builder.

PS.: I did not tested this code thoroughly, but I didn't had any problems so far.