Most individuals, save the incredible hulk, would find it impossible to pull a dangling, injured climber out with a standard z pulley single handed. You could both bring a double z pulley setup, but you'll need to make sure you've got enough pulleys; the friction of using just biners rolls back a lot of that mechanical advantage.
2 people on a 30 meter rope, for most folks, means the person is the crevasse is going to get their own ass out or the party's going to wait for assistance. It also means the rope's not going to melt/freeze into the crevasse lip - and thus require an extra length of rescue rope.
Revolvers (a biner with a built in pulley) offer a more versatile and lighter substitute for pulleys. Expensive, but I've got a pair and use them all the time for all kinds of things.
A pair of Tibloc's (which climb 8mm + size ropes) negate all the fuss of matching prusik line to rope size and enable faster self rescue.
If all else fails, climb down further into the crevasse to look for a way out. Just ask Joe Simpson.