I considered it, but just couldnt kill off my team mates.
haha yeah me too, I did a renegade run with intention to kill off majority of the squad but I still couldn't bring myself to NOT get ship upgrades or do a couple loyalty missions. I left Wrex in the tank, sold/gave Legion and Miranda, Jacob, Jack and Thane
died but the rest lived (and I saved all the crew). Sometimes it's so hard to be BAD.
a bit OT but.. I wanted to let Morinth kill Samara (and then let her die) but it didn't give me the option of who to save. (almost full regeade, maybe 20% paragon). Out of 4 full playthoughs in ME2, only first run with full paragon did I get the option on
who to let die, but being paragon I picked Samara. Will I ever get Morinth? that's a goal for next time.
voteDC is right, you need at least one person alive at the very end or Shepard will die.
That being said, there might be a way to end up with only Shepard & Joker alive if you have the Zaeed dlc.
If you kill people off in an order that lets you leave Zaeed holding the door with Tali & Mordin, he should be the only one of those 3 to make it back to the Normandy.
Then after you speak with the Illusive Man, go and do Zaeed's loyalty mission, choose to save the workers, then when Zaeed gets trapped you should get a dialogue option that will let you leave him there to die.
n.b. I have managed a playthrough where only Zaeed survived.