Here is a tip on how to start AutoCAD 2006 with a specific Workspace.
There is not direct way to start AutoCAD 2006 with a specific Workspace but it can be done with a script file.
Create a shortcut with this Target:
"C:\Program Files\AutoCAD 2006\acad.exe" /b "C:\CustomWS.scr"
CustomWS.scr holds this row where CustomWS is the name of the Workspace:
(if (/= (getvar "wscurrent") "CustomWS") (command "wscurrent" "CustomWS"))
The reason for why I made the code above like this is because of performance. It just set wscurrent to CustomWS when needed.
Then you can add as many shortcuts as you want for your different Workspaces.