As mentioned, you do not need to run any virtual machines. You do not need multiple copies of D3 installed either.
Find the file where you have Diablo installed.
Locate Diablo III.exe
Right click on it and select "Create Shortcut."
Move that shortcut to your Desktop.
Right click on the shortcut you just put on the desktop
Select Properties
In the "Target:" box, add " -launch" to the end of the line
**Do not make modifications to any box other than the "Target:" box.
**Only the program path and name need to be enclosed in quotes
Example:
"C:\Program Files\Diablo III\Diablo III.exe"
-launch
______________
Once you get that setup, I would use Autofollow. There is a link in my signature.
You can open a fresh ZIP of DB for the new account, or copy/paste the currrent one if the settings will all work as well.
I am also using YAR with customized window settings (sets all 4 of my windows on the screen to the same place every time, opens all of the games for me).
Point YAR to the shortcut on your desktop for Diablo.