Outlook Integration with SharePoint 2010 (Drag and Drop)

Recently, I was working on one of the SharePoint 2010 tender, User need to drag and drop the email and attachments from Outlook to SharePoint 2010 and SharePoint 2010 to Outlook. First I thought of propose Colligo outlook integration tool but the CAL licenses seems too expensive for our customer. When I look around I come across following tools.

1.) harmon.ie for SharePoint is an Outlook: http://harmon.ie/SharePoint/Product (Free for Outlook but limited feature). You can compare Free vs Enterprise edition @ http://harmon.ie/Products/CompareEdition

2.) OnePlaceMail : http://www.scinaptic.com/oneplacemail.html (OnePlace Express is free, but its limited to 25 users, Enterprise need to buy only server license)

3.) Third Sight (Singapore Base company) http://www.thirdsight.net/product_PS.html (I think implemented few government agencies)

4.) Connect for SharePoint : http://www.knowledgelake.com/products/Pages/sharepoint-integration-office-desktop-application.aspx

5.) SharePoint Email filer : http://www.sharepointemailfiler.com/features.asp

Some of above is server licenses and as well as CAL licenses. Overall I don’t know… if I custom develop using Visual Studio with Outlook Add-In not sure can we meet 50% of above product features?

I think it’s time to explore...