Accounting System Rewrite -- 3

We are looking for a full rewrite of an existing accounting/time management system that was written in VB6.

The software includes, but is not limited to:
-Various modules to manage data, such as sales, customers, purchases, banking, and accounting
-Enter quotes, sales orders, invoices, leases
-Manage customers, receivables, payments
-Create purchase orders, manage inventory, accounts payable
-Enter checks, create deposits, recurring payments
-Chart of accounts, general ledger
-Create new companies & projects
-Reporting for data related to every module

Requirements:
-Rewritten to be web based/multiplatform and mobile-ready
-SQL Server database (ported from MS Access)
-SSRS reports, rewritten from the existing reports
-Add robust user management with permissions by rank
-Add ability to change the data source on a per-module basis

There will be various other requested changes/additions to further upgrade the current software, which will be reviewed upon accepting a bid. Screenshots will be supplied, as well as source code if requested.

Please leave your estimate for payment & time frame for delivery with your requested bid, or if you would like more information, please make note of it.