Devil's Advocate...
To make this work, you've got to make a couple of dubious (or at least debatable) decisions. First, you have to decide that corpses are objects. I can't find a rule at the moment to confirm or deny this, but in my opinion, the fact that several spell targets make a distinction between objects and corpses means that corpses are not simply objects in the general sense of the game term.
Second, you'd have to decide that a Huge creature's corpse is the same size as a Huge object. Again, I can't find specific rules defining the size categories of different items, but there are a few different references to them obliquely.
Weapon Size says that, for example, a one-handed weapon is an object one size category smaller than the wielder. This means that a longsword made for a Gargantuan creature would be a Huge object. However, clearly it would still be much smaller than a Huge dragon corpse. Obviously, this will affect the necessary caster level of the spell.
Assuming you decide both of these things are true (that corpses count as items for the purpose of spells that affect items and that an item's size category is equivalent to a creature's size category), you'll wind up with a Huge construct that can't do most of the things a normal dragon could do (but maybe that's the way you want it). My advice is to make sure you allow your players to use the same techniques that you do. This seems like too good a trick for them not to use it themselves.