Just after the first of the year I bought a factory refurbished ASUS G750JW online ($909) and then upgraded with 16 GB of RAM and two top grade SSD's about $1450 total. It works great. Just finished editing a wedding with three cameras all AVCHD 1080i. You can see the test results on our PPBM7 web site if you register, it is about the 36th entry and the highest scoring laptop of the bunch
Yes, get the quad-core and dedicated video card; that will serve you much better for timeline work (without having to render).
Asus's gamer laptops, like Bill's G750JW mentioned above, are probably the best option at your price point. There are better laptops, but they are much more expensive. There are other gamers laptop models too (MSI, etc.), but Asus seems to be cranking out products with less issues than the others. Cooling, power supply robustness, GPU cooling, and drivers are all important and you will be crashing a lot if they are not all designed and built properly.
....I am "seconding the motion" to recommending an Asus gamer.....I've been using an i7 model for 3 years now, and it has been working great. Like Bill described, I filled both HDD bays with quality SSDs and upped the memory to its max. The new models, like Bill has, are WAY better than mine......a refurbished Asus would be a great deal...5 years ago I bought a dual core one, and it still runs GREAT......I could even edit on THAT,( only after transcoding). You MUST pick one with a dedicated NVidia graphics card, to get the best GPU performance while using the "Mercury Playback Engine"....ATI is still FAR behind with "open CL".....ONLY NVidia can provide the SUPERIOR CUDA performance in accelerating effects, scaling, and other tasks.
...One caveat....a NEW CPU is being released in September....the "Haswell E ". This will offer MORE CORES, (6 or 8), quad channel memory, and other improvements. I am sure a laptop version will appear which will push performance even HIGHER. Adobe recently updated PPro CC to handle 4K footage much better....it appears THAT is the direction that software and hardware are going......like the transition from SD to HD a few years ago. You may be better prepared for the future with a newer "Haswell E" machine later this year, along with an even BETTER NVidia mobile GPU, which may appear as well by then !!
Get the Quad Mobile chips only preferably with Hyperthreading. Mobile chips already have a significant performance difference than Desktop chips and the lower end dual core mobile chips are not enough to really process complex compression algorithms very well. The money spent on the laptop is lost when the performance is significantly handicapped by a CPU that cant handle HD AVC media or similar codecs.
Yes.....absolutely agree !!...NO WAY would I recommend any "dual core" CPU for editing....using it was PAINFUL !!!!!...but, I DID manage to do SOME work with it. Eric is very correct, the i7 quad core with hyperthreading is a MINIMUM ....the current mobile i7 Haswells are good....like Bill's machine......new ones coming, should be even BETTER !!