I use something like this on Linux, it's called tilda (there are also various similar implementations). It's both awesome and a curse to me. I have it bound to alt+kp_enter and I always keep an irssi/irc session running on it. Every time I need to chat with my friends on our IRC channels I just hit alt+kp_enter and it opens, it's a curse because now I'm always chatting and doing other things while I work, which detracts a lot from my productivity.
Still, really awesome! Nice to be able to share something like this with our windows friends.
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.
Still, really awesome! Nice to be able to share something like this with our windows friends.