Family Sharing when having different accounts for purchasing and iCloud

I have two Apple ID accounts. One that I use for making iTunes purchases (which I had way before @me.com or @icloud.com existed) and the new @icloud.com account that I use for everything iCloud related (Messages, backups, etc).

Now that Family Sharing exists, I want to bring my kids and my wife into the plan, but from what I've seen, I wouldn't be able to use my icloud.com address since all my purchases are on the other Apple ID. The problem is that either I would need to stop using my icloud.com ID or purchase everything again?

I know one of the most requested features has been to be able to merge accounts and I know I am not the only one in this situation. Is there a way in iOS 8 Family Sharing to do just that? I wouldn't mind removing my old Apple ID account as long as I can transfer all my purchases to the new icloud.com ID.

Otherwise, I guess Family Sharing is out for me (and for everyone who is on the same boat of having 2 different Apple IDs).