I think MS Outlook Business Contact Manager (BCM) is underrated and under marketed. Not sure why, but you might want to review the options. You can customize your pages and communicate between your outlook business contacts and MS Accounting. I am not an expert, but I know you can use ASP to interface with the SQL tables to produce all your expected web input and report options. I bought a book on the topic but have not had time to read it yet. Good luck.
http://office.microsoft.com/en-us/ac...366591033.aspx