Apple - Is there any multiple terminal emulator for Mac OS?
iTerm 2 claims to be able to do this.
Edit: I just downloaded it, and it seems to work well enough that I think I'll switch from iTerm 1:
I'm not sure what's going on with you and macports, but I just installed tmux using macports. it took about 30 seconds, and was completely painless.
FWIW, I've subsequently spent enough time with GNU screen that I basically just use it for everything at this point. iTerm is nice if you want a local, mouse-driven multiplexer, but almost everything I do is server-side at this point, and doing it all over one SSH connection is much better anyways.
Terminator was just ported to Mac OS X via the homebrew package Manager.
brew install terminator
See the PR or the recipe.
Tested on OS X 10.9.2 the main functionalities work.
Install GNU Screen, or TMUX via macports/homebrew or by compiling it by hand.