Make any windowed application 'Always On Top' without keyboard shortcut?

Dexpot does that, it enables a "Clever use of title bars":

The title bar as well as the minimize, maximize and close buttons can be assigned with further functions (Role up, Minimize to system tray, etc.).

Always on top is one of the functions. You could, for example, make a right click on the maximize button activate the always on top.

Download the AlwaysOnTop installer and install it (choose the latest release). Run the app from Start -> All Programs -> AlwaysOnTop. It sits in the system tray. Click the icon in the tray, click "AlwaysOnTop", and then click the window you want to stay on top (the cursor will be the cross while waiting for the window).

Full disclosure, I am the app author and this was built using .Net (C#). Full source can be found at the link as well.

This is off the OP's original question, but seems like a good place to share information about 'always on top' utilities, even if it does require a few clicks.

From a programming standpoint, writing a simple utility like this is a very simple exercise. Maybe that's why there are so few solutions out there, or perhaps why there are so many home grown ones.

It's hard for me to trust utilities that are downloaded from somebody's Google Drive or Dropbox account. But I do trust Nir Sofer of Nirsoft. He has a tiny app called WinLister where we can set a window to be always on top. It's not very user friendly if you do it often, but I only occasionally need to pin a window to the top, so it works for me.

http://www.nirsoft.net/utils/winlister.html