Yeah, I already did a Fail Shep where I tried to kill as many as possible. It was actually a pain, since you really need to carefully calculate how the Hold the Line segment will go to kill all but two team members (all but one will still result in Shepard's death). This chart
is of immense help in planning this out.
As I recall, doing it required:
Do not recruit Zaeed until after the Suicide Mission. He can be left to die at the end of his loyalty mission if you do it after completing that, and if you do recruit him beforehand, he messes up the math on Hold the Line too much, even if you kill him some other way.
Any teammate that will survive to the Hold the Line segment should not be loyal. It becomes quite difficult to kill off who you want dead at that point if anyone is. Also, the high-score teammates (Grunt and Garrus) should be killed off before that segment, because even when not loyal, they substantially raise your score there.
Miranda cannot be loyal, period. The way the math works out with her completely prevents her from being killed if she is. And even if she isn't, the best way by far to get her killed is to bring her to the final fight (both your companions in that fight die at the end automatically if they're not loyal). This one I learned the hardest way possible - I did the file romancing Miranda the first time, which requires her to be loyal, and found out only at the end that I couldn't kill her. So I had to re-do the whole game to get what I wanted (only Morinth and Thane alive at the end).