I think it's pretty cool, kind of like a boss item. Might want to consider making it like that. You could get some major experience points from one of these bad boys. What you could consider is making a different dragon that spawns from these eggs that you can craft. This dragon will be easier to beat and drop less experience, but it'll give you a boost in your experience travels. Maybe even give you a couple eye of enders. If this is the case, might as well make it harder to craft too, like outline the edges with diamonds.
You might want to check, but the last time i spawned enderdragons on the overworld in 1.0.0, when they die, they still spawn the end portal. So if you spawn many dragons, your landscape is going to be littered with end portals. :biggrin.gif: