Looking For Directory Solution

I have an upcoming project and I wanted to reach out to the awesome community at WPMU.

Here’s the need:

I want to a create a directory site with some very specific needs:

1) Custom fields

2) Sales must be able to add the listings.

3) Sales must be able to assign each listing to a specific client.

4) The public can not login or create their own listing as each listing requires pre-payment.

I can use WP-Types, etc to create the actual interface, custom types, etc, etc, but where I am looking for advice is the workflow where I have a salesperson create a listing and then assigning it a new user they create with the account.

I am almost thinking this will require a custom submission form for sales, but I would like it “cleaner” if possible.

I did see the directory listing at WPMU but I am not sure it will be custom enough…

Thanks for any insight.