Two years ago I was in a similar situation. I had 6 weeks to find a fully furnished apartment in Munich from 800km away. For me the response rate for furnished apartments was 100%, although some simply said the apartment has been rented out already.

I also turned to crawling. I regularly crawled IS24's furnished apartment section and put new entries into a Google Fusion Table. That way I could filter on fields and see the apartments on a map at the same time. This wasn't automated as much as the original poster's solution. But my main requirement was that the apartment be near a subway station of a line that stops at my place of work, which is not that easy to automate.

After about a week I found an apartment that was rented out by the owner directly (none of that agent fee nonsense). I was the first to contact the guy - a few minutes after it was posted. I had to decide if I take it the same day. Based only on pictures... It was a good deal. Colleagues of mine were paying MUCH MORE and got MUCH LESS.