Module recommendation for simple Client Management Site

Hello everybody. First time Drupal user here, building a pretty simple site to do some Client Management. I already have CCK and all the basic modules installed, just need a few quick recommendations on the other stuff. Here are the details:

1. Admin (me) creates new user (client), password is generated and e-mail sent to user.
2. Node is auto created for user and permissions set that only that user (and admin) can access it. (sandboxed)
3. Admin can create project page(s) on client's node (as child) and upload a flash video.
4. User can add comments to the project, 2-way email notifications sent when admin or user adds a comment.
5. User can attach a file to the project page.

So its not to hard, but not to simple either. I already have #3 basically done by using FlashVideo+DashPlayer, and comments are working. For #2, I was thinking of using Taxonomy Access Control to do the user sandboxing, however that seems like it would require defining a 'role' for every user (client). This sandboxing seems to be the hardest part, so I was wondering if anyone had any other module recommendations to do this kind of thing, besides TAC.

I can program procedural PHP and am willing to write a module if need be.

Thank you!