I use Guake for this. I have it configured to fire up Tmux and then I have it bound to Ctrl Alt T, and it drops down a terminal anywhere I am: any desktop, any screen. I didn't read the entire article (I don't think it's particularly well-written or stems from any particular expertise in the domain), but I doubt the author addresses the huge advantage I see with terminal multiplexers, which is it allows me to cut and paste from the terminal without using a mouse, and allows me to log scroll back and capture sessions effectively in any terminal emulator I use, not just a fancy one like iTerm2.

This sounds like a great use case for tmux. Have one (1) terminal open, and as many panes/tabs/whatever as you need.