How can I access volume levels from the command line on Windows 7?

This question was asked and answered on StackOverflow: https://stackoverflow.com/questions/4640106/how-to-get-current-volume-of-system-sound-device-in-windows-7

The answer: https://stackoverflow.com/a/4640225/704977

You're looking for the EndpointVolume API. This is part of the new audio APIs that were released in Windows Vista, and it can be used to get or set the master volume.
... There's a complete managed wrapper library available on CodeProject: Vista Core Audio API Master Volume Control.

I know you said you did not want an AutoHotkey solution, but I believe the AutoHotkey API has what you are looking for:

• SoundGet
• SoundGetWaveVolume
• Related: SoundSet, SoundSetWaveVolume, SoundPlay

You do not need to create GUIs or use hotkeys with AutoHotkey. You can write powerful command line utilities by compiling an .ahk script. That being said, you will want to look at the FileAppend command for working with stdout.