I'm not sure the fax number even works, but I took it off of my reservation form from last year. 407-352-2792 and addressed it to the room controller. I just told them what we had booked and that my two girls would be very excited if a (complimentary) tower room overlooking MK were to become available. It worked!!
That stay was only 4 days - I wondered if that's why we got the upgrade. Then we moved to Poly. I sent the Poly a letter also, but just told them what building, floor, etc. I wanted. Was able to get those requests too - not upgraded to concierge (wishful thinking there!!)
However, one year we did get a concierge upgrade, if you can believe that, at the GF! I had faxed a request for Conch Key and they gave it to me. Little did I know it had been converted to concierge while the main bldg was being renovated!
So, you never know - a little pixie dust may be sprinkled your way!
Cutekatcar