Can you dynamically resize Windows Command Line window?

In windows 7 use the mode command.

mode con:cols=80 lines=40

This is done via the Properties > Layout tab of the window or the shortcut.

Detailed instructions - How to Make the Windows Command Prompt Wider

You can change the screen buffer size in the Layout tab of the Preferences dialog (click on the icon in the top left corner of the window to get to the menu). Making the screen buffer bigger will allow you to then change the window size.

If you do this though, the text will extend past the window and you will have to scroll to see it. There is no way to dynamically change the screen buffer size like you want AFAIK.