I needed a small, simple, unobtrusive, floating peak meter for my microphone, but couldn't find one. So I wrote it myself.
You can download the program and use it as you wish. But note that you'll use it at your own risk and I won't support it. You are not allowed to redistribute the program, though.
The peak meter can be resized horizontally and it will remember its last position on the screen. If you have two or more microphones you can click on the peak meter to switch between them. (Thanks to WinMM you only see the first 32 characters of their names, though.) It will remember the ID of the device (but not the device) that was last used. That's all, folks...
The program was created using the Common Lisp compiler from LispWorks.