iTerm 2 equivalent

As suggested in the iterm2 website itself (under "Hotkey Window"). There is guake, tilda and yakuake. Which can be installed from repositories.

I personally use guake. If you use unity, I have written an indicator for guake although you can easily enable systray in unity as well.

You can try terminator, search for it in the Software Centre.

I'm not sure whether it provides the feature you require, but it offers some other good features of iterm2 like horizontal and vertical window split

Since April 2020 the source is hosted by github.

tillix is the most complete alternative I found so far