I found three castles. The battlecastle and the dragonmont castle in addition to the adventure castle. They look pretty cool, but I think Lego has some really neat castles too. Knight's Kingdom, Black Castle. Lego also has Batman's Arkham Asylum. The Royal King's castle is 99.99.
BlackBeltBoy loves the starwars legos! I have come to the point though, that he has to buy them with his allowance money. Some of the kits are only $10 and under, others are $20. The larger items are pretty expensive and so we do not have those yet.
He has a couple of other castles including a Little People version that was initially Jr's.
But he's pretty insistent on "Imaginext."
And yes, he would know.