That would put the per-comfig'ed machine with 780m costing around £1500+.
COLOUR CHOICE LCD Back Cover (WLAN) Alienware 17
PROCESSOR Intel® Core™ i7-4700MQ (6MB Cache, up to 3.4GHz w/ Turbo Boost)
OPERATING SYSTEM English Windows® 7 Home Premium (64 BIT)
GRAPHICS CARD NVIDIA® GeForce® GTX 780M with 4GB GDDR5
MEMORY 16GB Dual Channel DDR3L at 1600MHz
HARD DRIVE 750GB 7200RPM SATA 6Gb/s
LCD 17.3 inch (439.42 mm) WLED FHD (1920 x 1080) Anti-Glare Display
OPTICAL DRIVE Slot-Loading 8x SuperMulti Drive (DVDR/RW)
WIRELESS CONNECTIVITY Broadcom 4352 802.11 ac 2x2 and Bluetooth 4.0
PRIMARY BATTERY 8-cell Lithium Ion (86 wHr) Battery
OFFICE SOFTWARE Office not included
SECURITY SOFTWARE Antivirus not included
SERVICES AND SUPPORT 1 Year NBD with Premium Phone Support
ACCIDENTAL DAMAGE PROTECTION No Accidental Damage Protection
£1,948.99
I would say much more then 1500+
