Salesforce custom software - Only for Experienced Dev

Need customization of salesforce for real estate sales business fully integrated - Flexible property master: Development, phase, unit, weeks (if fractional) -Ability to schedule property tours by time/date/sales with tour record -Ability to add one or multiple prospects into tour record - Need inventory database for managing inventory, amenities, pricing etc. - Need flexible method to add inventory by lot, unit etc. - Need method for creating sale with table driven contract types. -Select inventory -Confirm price -add table driven discounts -select down payment -select interest rate -determine monthly payment -checklist of required information - Create/Print Real estate sales contracts - Manage sales status - Pending, Full Down Payment, other table driven status codes - Real estate inventory management (automatically reduce when sold) -create salesman commissions based on sales role, contract type - Need easy-to-use report write to create report More information later. Probably 500 hours. Progress payment can be made. Needs to be fully integrated into salesforce with same look and feel. I will flush our design for selected