Antique stores have such a thing. Or, just ge a locking trunk tall enough to hold your bottles.

If you already have the cabinet a simple lock would work but other than that i dont know where you can get one fast.

Go out and buy a cabinet then go to home depot and but a lock bracket.... then lock the cabinet. BOOYAH!!!!

Hide the alcohol, say you gave it away, just until you find a proper liquor cabnet.

IKEA has a really cute cabinet that locks it is in the p/s series and i am buying one for my booze cabinet so i can keep what i have...damn roomates!!