Can a custom champ break the game?

I'm always interested in champ development of LoL. If you could combine any 2 champs into a custom champ, who would you pick? Here are the rules:

1. Pick any 2 champs.
2. Pick a champ model. This will determine their looks, skins, base stats, attack style (i.e. range vs melee), and resource bar. The resource bar is important because lets say you pick tryndamere as your model and lee-sin as your 2nd champ. Your champ will have a Fury bar as a resource, so basically the only moves you can use from Lee is his ult (which requires no resource) and his passive (for attack speed bonus only).
3. Pick a passive from the 2 champs.
4. Pick 3 abilities from the 6 you have available. See resource bar explanation above for possible limitations. If you pick a champ with 2-in-1 abilities like Nidalee, Jayce, Ellise; you will only have access to both abilities if you take their ult too. Otherwise, you only get the ability in the form that they start the game with (eg. only Ellise's human form skills).
5. Pick one of the 2 ults.
6. An explanation why you think this is a good combination, and if this custom champ can break the game.

Here's a quick example.

1. Leona + Blitz 2.Leo's model
2. Leo's passive 4.Q - Leo's Q (stun) W - Blitz's E (knock-up) E - Blitz's Q (grab)
3. Leo's ult.
4. With 40% CDR, both Leo's stun and Blitz's power fist gives a 1 second stun on a 3 second cooldown. By rotating these 2 skills alone, you can keep a single opponent stunned 66% of the time. By throwing the other abilities into the mix, you can cc a single opponent for about 6 seconds. I think his has he potential to be gamebreaking.