The main reason for this is because this processor requires a new cooling and power infrastructure that isn't found on most motherboards and cases.
If you are building a box from the ground up, you can spec out more airflow and power, and it won't be a problem. Plug it in to a Tyan S2882 you have lying around, and suddenly it could be a problem. AMD doesn't want this, so it is only selling them to people that can deal with it.Next year we can expect a 2.8GHz Opteron along with a 2.6GHz part with a 95W TDP.