I sat 2級 in Tokyo this July and received scores of 222/400 (overall), 62/100 (文字・語彙), 67/100 (聴解) and 93/200 (読解・文法).
Now I've left Japan and am resuming my final year of study at university, but I would like to possess the JLPT before I graduate next June.
Am I being ridiculous to think I can study enough to pass 1級 when I'll also be studying final year economics, continuing my Japanese study in classes, and attempting to learn a little Korean in my free time? Or should I just take the safe option and apply for 2級 for an easy pass this time around? (I don't believe that I really did myself justice studying for 2級, especially as my girlfriend in the same student dormitory cut heavily into my time.)

I would say no, not unless you put in serious study time. It is a challenge just to pass JLPT1 within 1 year of passing JLPT2.

GF living in the same dorm would be nice. All (something else) all the time.

With full time study, probably doable but still difficult. With all that other stuff you have going on you have no chance.

I've passed 2級 and am taking my time getting towards 一級, though Im not studying for the test specifically. Someone once said to me that going from 2 -> 1 seems almost as much work as going from nothing -> 2. So far I think thats probably reasonable, there is a big jump.

If you had started studying the day after you took 2kyuu, you'd still have a -very- hard time passing 1kyuu in December, even if you studied nothing else.

If you aren't pretty sure that you can pass 1kyuu today, I wouldn't take it in Dec.