AutoCAD Client Server based products? AutoCAD Server version?

Is there any Client Server based products in AutoCAD community? How about an AutoCAD Server Version with client tools made in ActiveX or Applet which can be operated through internet browser or lightweight client workstations equipped with SQL interface? I see the following advantages.

1. Easy Integration and management of Data.
2. Work can be distributed all over the world. It is not limited to a location
3. Same file can be shared by multiple users at same time (Just like RDBMS records)
4. Can handle very huge projects (say for example a huge geographic area development) as easy as a small project.
5. Clients can watch the progress of the job and comment online so that a lot file conversions and transmissions could be avoided.

And I see these disadvantages too

1. Don't know how practical it is to store AutoCAD Data in an RDBMS or similar format.
2. Don't have any idea of implementation costs as compared to the existing systems.

Have any thoughts?