Custom web-based property management website

Custom web-based property management website with login accounts for property manager (admin control panel), clients, and tenants. Must allow for tenants to pay rent via Credit Card. Site to have very clean and professional look possibly using a template. Must support upload and viewing of documents, property photo gallery, gallery photos can be uploaded by a single zip file, and excellent organization. Modification of existing open source property management or e-commerce software accepted and recommended. Must have these built in capabilities: calendar, programmable reminders which email members and produce alerts on their login page, rent entry, tax expense entry, insurance expense entry, complete property profile page, property inventory like an e-commerce site, organized documentation upload/download capabilities, direct links which can be sent to clients, potential for multi-language support, export data to quicken/excel, search tool, and must be set up with source code to be available for future custom modification. Programmer to follow my instruction and detailed modifications to appearance and functionality of the site. PHP/MYSQL preferred, but open to better suggestions if they exist.