I'm having trouble getting the list from Ian in the Old Mine. I ask him for it, but he says something along the lines of "Anybody can ask that!" and nothing more. What the hell have I done wrong!?
I've read many walkthroughs, but nothing seems to document this problem. Am I missing something obvious? Maybe I should just beat the list out of him >_<

Oh, this! It's not at all obvious, unfortunately. From memory you need to go back to Diego and ask him why Ian would give you the list, and you will then be able to go back to Ian and tell him Diego sent you. You were expected to ask that before leaving for the mine.
As a general rule you should always exhaust all conversation options when talking to someone, although this is one of only a very few times where missing one can actually matter.

Damn, I was too eager to go to the mines that I neglected that. Thanks man.
But seriously though, why bother with another dialogue option? Why not have Diego give you ALL the information you need to know in one hit? Why bother programming Ian to say "Anyone can say that!" ? Methinks someone on the team did it for shits and giggles...

many thing in Gothic were done for shit and giggles it seems. going so far as tormenting the player ;)
some dialogue options are done that you don't realize you branched away in a certain direction and can't take it back / change the conversation anymore.
e.g. the guards try to get bribes from you, you have 2 "negative" responses while only ONE has you refusing to pay, the other one leading to you giving away ALL the money you have (even more than the original asked 10ore)