A few other monster classes got an ability where they could eat magic items and gain their benefits. For example, in this case if a dragon ate a mithril fullplate, even if it wasn't built for it, it could gain the benefits of it while in either dragon or human form.
This would also allow the dragon to enchant its natural weapons, although it would have to eat a weapon for each natural weapon it wanted an enchantment on. So it would have to eat three flaming weapons to get the flaming enchantment on its bite and claws, and would have to eat 3 adamantine weapons to get an adamantine bite/claws.
There would also be the limitation that, while you could eat another item to remove the effects of a previous one, you don't get the previous item back. So, if you decided you wanted adamantine full plate instead of mithral, you don't get the mithral full plate back.
Not sure whether this would be exceptionally prone to abuse, or a bad idea. I just think it makes sense for a dragon, and was curious whether it would work.
The items would probably appear on their alternate form so that it made sense the alternate form got the benefits. The items still could not be sold.