Dunk & Egg is one of them, without a doubt. And there's a good chance that another will be about Robert's Rebellion.
As for the other two, my guesses would be Aegon's Conquest and the First Blackfyre Rebellion.
The Dance of the Dragons would be another possibility if it didn't feature so many dragons. The FX budget would go through the roof with what... 17 dragons, if memory serves?
Aegon's Conquest would do nicely for a one off event. And the First Blackfyre Rebellion has so many interesting characters and intrigues before the fighting even starts that it could make for some interesting TV.