Can recommend guake[1] for linux users, it looks decent and works like a charm. Modified the code a bit to color the active tab so it's easier to spot[2]. I think it's also included in the most recent version, i.e. if your distro has it or if you build it from source.

[1] = https://github.com/Guake/guake/ [2] = http://i.imgur.com/njoTQXe.png