8-10 sq. in. isn't large if one measures the connection to a box or chassis. Remember these devices will heat up VERY FAST. One needs all the heat protection one can get.
There are TO-220 heat-sinks. I wonder though about one designed for one device. These MOSFETS are flaky when it comes to heat. It is because they are avalanche devices and have a very small linear area, hich is probably why they give so much trouble as RF devices. On the other hand, they are cheap...
