I'm trying to find Gustor, the Conjurer in the college. All the other NPCs are in their beds or walking about. I suspect the character was offed at some point but really want to start the quest he gives for the ritual spell. Is there a console command or a trick to finding this guy?

Phineas? He somtimes sits in the library.

Phinis Gestor? He sleeps in the Court hall. You sure he's dead? Because I'm pretty sure he's tagged as essential so afaik he can't be killed randomly.

Finding the mages in the college always is a hassle for me too. Worst mage guild design ever. Sometimes waiting a couple of hours helps, as well as the detect life spell so you don't run around in dumb circles checking each room.

He usually hangs out in the Arcanaeum during the day. If you still can't find him then the console command is
Prid 0001C199
Moveto player
Good luck.

lol. That is a useful trick.
http://www.youtube.com/watch?v=ABykKiJaEgU

I actually used player.moveto only to find that there's an entire tower of the College (of which I seem to be guildmaster) that I never even knew about. I guess I need to get around a bit more.

lol.....at least you found him......now get out and have some fun in your college!

The mage college is a bit confusing because there's the students quaters where some of the teachers seem to hang out also, which can throw people off.
There's another section, to the right of the entrance to the college (opposite to the students place) which is where you may find him. This is usally where sneaky feralda seems to hide when you need her most, also!