WordPress mu domain mapping

Essentially, no. If you look at how that plugin stores its mappings:

mysql> desc wp_domain_mapping;
+---------+--------------+------+-----+---------+----------------+
| Field   | Type         | Null | Key | Default | Extra          |
+---------+--------------+------+-----+---------+----------------+
| id      | bigint(20)   | NO   | PRI | NULL    | auto_increment |
| blog_id | bigint(20)   | NO   | MUL | NULL    |                |
| domain  | varchar(255) | NO   |     | NULL    |                |
| active  | tinyint(4)   | YES  |     | 1       |                |
+---------+--------------+------+-----+---------+----------------+

There simply is not a place to put a path.