Complete Business Management Accounting Sofware Program Needed

A plywood wholesale distributor needs a new software designed. Currently we run an outdated linux legacy dos system and we need to update our software. software would need to include following inventory management order process (ability to email and preview) quotes order return (rma) invoicing and statements (ability to email and preview as well) purchase orders to vendors customer management payables and receivables reporting function that will analyze all of the above (for example, customer analysis, inventory item analysis, price sheet, vendor analysis etc etc ) payroll salesman commission reporting credit card processing quickbooks import/export (check writing would be great as well if possible) ability to import customers and inventory items from a csv or xls format spreadsheet. ability to design orders and invoices to fit into our pre printed forms the software needs to be able to compute dimensions. for example products are bought and sold by individual piece but are computed by sq foot price. example 1 sheet (piece) of a 4x8 board (32 sqft) at 1.00 per sq ft would equal 32 dollars. all documents need to show thickness and dimensions including the description MUST have ability to print on a dot matrix printer as well as laser. ( we need to print quickly on the dot matrix) need a multi user system that keeps track of what each user does throughout the day and has a user lock (data entry people cannot access the main accounting modules) a big plus would be to have the source code so we "own" the system we would need to know the suggested hardware requirements as well. figure there would be like 3,000-4,000 customers and 3,000-4,000 inventory items int he system with an average of 30 orders per day. would like to see some sort of sample if possibile. if you have worked on something similar maybe you can send us a download link or do a screen share to show us what you have done ( or send screen shots). if you would like some screen shots of our current program for reference purpose please ask. thanks