I won't complain about the amount of Wyvern Posts, All i want to say is I've always wanted my own dragon (as a kid) it would be the most awesomest-eststest pet ever, and i don't often use that word. (in fact it's my frist time ever saying that)

Having a wyvern would play right into that childhood fantasy making the game all that more awesome to me, regardless of how it's achieved.

I for one think you could make it a quest one where at the end you decide whether or not you want to give physical form to your inner dragon or further harness it within your own body thereby granting you the skill "Summon Wyvern" or in the case of the later, a slew of breath attacks or the like that you can use at your leisure.