Msi / Alienware
I have been researching the same, and pretty much have the same budget.
It comes down to a choice of two now for me.
1 - Alienware M17xR3 , which has a Nvidia 580GTX-M , Intel® Core™ i7 Processor 2670QM (2.20Ghz, 6MB, 4C) , 4 GB RAM , Win7 Home Premium 64 bit , 2 x HDD bays (with only 1 filled but you can spec it for two or 1 + SSD)
2 - the MSi GTX series (available from OCUK - just look under the laptops section). The Msi series only does Nvidia 570GTX -M cards though. It also has the same i7 processor, and 8 GB RAM , but includes 2 x 750GB HDD (in RAID 0 for performance and space 1.5TB in all)
I cannot link to the alienware as it is for sale only by competitors, but the link to the MSI is here :
http://www.overclockers.co.uk/showproduct.php?prodid=LT-057-MS
Both will set you back around 1350 , which leaves room for extra memory or hdd or carry-case upgrades.
Hope this helps your decision, mine has been agonising , especially as the MSi deal on OCUK expires tommorrow, and the alienware deals expire on the 4th Jan. Gonna have to spend soon !