complete customer data and accounting package in excel

I am looking for someone to complete a customer data and accounting package in excel that contains individual client details with payment in and out, invoicing and billing, inventory management, financial reporting and analysis capabilities. It would be nice for the package to also have the ability to integrate with other systems, though this is not absolutely necessary. Most importantly, the package should be able to manage customer information. I would like for it to be organized and easy to use. If you think you have the right skillset to make this a reality, I am excited to see your proposal.