Originally Posted by vidder 
Is it something they can put together in one month, together with new voice acting and so on, or does it take longer?
For BDtS, definitely longer. Working out the DLC development processes and trying to increase the scope of what we could do beyond a brute-simple UNC took, IIRC, three months, and pulled several people off Mass 2 preproduction for the last month.
Future DLC, assuming there are any (and I don't know what the plans are myself), would be shorter, since we know what does and does not work.