PHP / MySQL Invoice Script

Project Description:
I require a simple invoice billing system. I am aware of all free versions an they do not suit my needs.

Specifically, I require:

- ABILITY TO ADD AS MANY LINE ITEMS AS I REQUIRE (COULD BE AS MUCH AS 30.

- ABILITY TO HAVE INVOICE TEMPLATE EDITABLE.

- NO SMARTY TEMPLATES - JUST HTML

- CLIENTS CAN VIEW INVOICES.

- ADMINS CAN ADD INVENTORY ITEMS.

- CAN E-MAIL INVOICES FROM SCRIPT - NO NEED FOR PHP FOR ANYTHING FANCY.

- CAN SETUP A REOCCUING INVOICE (EG: HOSTING PLANS).

- ADMINS CAN ADD COMMENTS TO INVOICES AND LINE ITEMS WHEN CREATING AN INVOICE.

- SCRIPT CALCULATES TOTAL VALUE OF TAX CHARGED IN A GIVEN TIME PERIOD EG: 7%.

- ENTIRE SYSTEM *MUST* BE XHTML V1.0! NO EXCEPTIONS.

Admin Features:
can add inventory items.
can create manual line entries & notes for invoices.
staff members add, create & delete invoices or clients.
can edit an invoice after it's been created.
can edit client details and create viewable client notes.
displays outstanding / pending invoices upon login.
tracks unlimited expenses (like fuel, inventory parts, etc.).
records tax, expenses, and invoice amounts for the tax year.
tax values can be edited and changed at any time.
you can e-mail a notification of new or past due invoice.
integrated backup / restore system for your database.
edit almost every aspect of the administrative or client GUI.

Client Features:
can login display, print, and e-mail invoices.
can view & print contact information as well as service notes.
can change their ICDBILL account password.
can request support for on-site or off-site service.