[quote name='Blumpkin']Quite possibly longer. The third book, "Storm of Swords" is going to be filmed as two seasons to maintain accuracy with the books without leaving a ton of stuff out. I would not be surprised if "Feast for Crows" and "Dance with Dragons" are filmed at the same time, but as three seasons for the two books (since they happen mostly simultaneously).[/QUOTE]
That's dangerous territory though. To have a show with this budget stick around for 10 seasons or more is going to take not only keeping the ratings they have, but raising them a bit as it goes a long. Not saying it won't happen, but look at the history of shows on HBO.
While I'm sure the budgets of Sopranos and Sex and the City (off-hand the longest running HBO shows I can remember) surely got huge near the end, they always held and gained in the ratings. And both those shows only went 6 seasons and neither budget is touching Game of Thrones.
The only two shows that actually ran longer were 30 minute comedies. Entourage and Curb. And those have seasons of 10 episodes and or, some very short seasons (Entourage's last was 6.)
Game of Thrones actually making the entire book run in television form, with some books split in two, would be unprecedented for HBO by almost double their longest running show.