the more power i7 quad core and discrete graphics usually have less battery life and are in bulkier cases. The Ultrabooks and 2 and 1's of today come with the U processors which mean cooler, lightweight and better battery life. The quad core i7 with discrete graphics tend to have bulkier for better air flow for cooling since those top of line components generate heat and use power.

Here is a good machine. These machines are getting better with battery life every new generation of processors. This does have a 6000 series the 6700HQ is under 2000 and 6820HQ is just above 2000.

http://www.dell.com/us/p/alienware-17-r3/pd