"Is this at least possible?"
Of course it's possible.
But you're asking for a replacement of {wp_}list_authors() to output users within a certain role. Here's a plugin which provides that:
List Authors By Role plugin
Download plugin | View source
Download the plugin file, upload it to your plugins directory, then activate List Authors By Role under Plugins. You can make use of one of two functions (i.e. template tags):
<?php list_authors_by_role(); ?>
<?php szub_list_authors_by_role(); ?>
Both accept the same parameters as their internal WordPress counterparts, but offer an additional one to restrict by role.
The new parameter in list_authors_by_role() is appended to those for list_authors(). Using szub_list_authors_by_role(), pass the 'role' parameter like so:
<?php szub_list_authors_by_role('role=contributor'); ?>
Separate multiple roles with a comma:
<?php szub_list_authors_by_role('role=author,contributor'); ?>