With respect to the phone, if they made one, I'd think it would have to be basically a 3DS with a phone built in, not a new platform. But if that were the case, it would be too large, or the screen and controls would be too small. The form factor would also just be weird to use as a phone. I personally think that's a market they don't want to get into -- working with phone carriers is notoriously awful, and it's not like their handhelds are doing bad on their own.
I'm not sure why people would buy a new non-portable home console to play the same games they're playing on the smartphone they already own. I agree with the others -- they won't do themselves any favours chasing smartphone games.
Angry Birds in particular seems weird -- it's popular because it's a simple, cute, $0.99/free cell phone game. I don't think anyone's buying a new phone/console to play it.
They really do need to better integrate their online stuff. I should be able to log into every system with my Nintendo account, and add friends (across systems) by entering their handle/email/phone. Virtual Console/WiiWare/eShop games should be stored on an account, not associated with the system. It''s a good thing these systems are so robust, because I'm sure getting your games back if your system dies is a huge pain.