You either like places to explore that are based on unusual objects, or you think they are impossibly twee and you cannot contemplate using them in a serious game. Whichever you are, take a look at this before dismissing it out of hand...
This isn't a fortress/dungeon based on the shape of a dragon, it is one built inside the remains of a real one! Start thinking of just how big dragons can grow, and imagine finding the remains of a really ancient giant one... for that is how the backstory provided goes. This provides a convincing rationale for the construct as it is presented, and even suggests what might be happening there and why your characters might have occasion to visit is well - and that's before you get to the selection of scenario ideas provided.
Interestingly, this is not a construct built on the bare bones of a long-deceased dragon. So exploration can take on shades of a fantastic journey through the innards of the dragon, as well as an assault on whoever dwells there. It is likely to make for a high-level adventure, as anyone who can make such a thing come to pass is going to be extremely powerful.
The maps themselves are inventive. They evoke, for oldsters like me, memories of all those hand-drawn maps done on squared paper, as this is indeed the basis for them, none of these beautiful drawn-on-the-computer graphics here but real hand-crafted sketch maps.
Never mind who might be here - and plenty of ideas for you to flesh out are provided (I won't say what, in case you decide to use them as given, and your players read my reviews!) - the actual setting itself can provide challenge and danger of its own. It's not quite dead, you see...
You will need to do some prep work before using this, of course. Select monsters, stat up everything else that's in there, organise the treasure and other loot and so on... as this is not a system-specific resourse.
The one thing that is not mentioned is the smell. I don't know about you, but I reckon the, er, back end of a dragon gets a bit whiffy!
An unusual adventure location with plenty of potential. Could be fun.