We are starting a business offering Private PO Boxes, we will have a physical shop with our steel PO Boxes lined up inside the shop and our client have 24/7 access to collect their mail and also have access through the internet to see what post they have.
There is a similar business operated in New Zealand called (privatebox dot co dot nz) and I am looking to have a similar website, I was looking at WHMCS application and I found that we can do most the things we require using it, like client billing, CRM, Support Tickets etc... it is ofcourse designed for web hosting companies and our business model is very similar to web hosting but we keep our clients post mail.
I think we can customise the Support area to tell our clients what mail they have and they will responce back telling us what to do with the post mail, i.e. forward it to their physical address, shred junk mail, scan and fax or email phone bills etc...
I hope I gave you a proper explanation about what we are after, please carefully review the above site and provide me with a quote for full customization of WHMCS and full site design.