Yes that's a good idea for a feature but it's up to Ivo to decide whether to add it. There is no built-in function in Windows for doing both at once so it will have to be done with a script. Also, there are other concerns when adding it to Classic Shell like localized/translated text which must be available in other supported languages for this action.
As a workaround, you can do this tweak which uses a VBScript: How to lock your PC and turn off the display with one click
(
http://winaero.com/blog/how-to-lock-you ... one-click/). Because the Classic Start Menu is fully customizable, you can add this anywhere in your menu.