Config pricing guesses:
i7 - $200
GTX 680MX - Between $200-$400
Fusion Drive - 1TB $250/3TB $550
768GB - $1200-$1300
So you can expect paying from $2399 and up to $2599 for your config model.
I Am Guessing Around $3200 - $3400, as long as you don't go for 768GB SSD
Going with:
27" 3.4GHz quad-core Intel core I7 with 8MB L3 cache
8GB Ram Upgrade to 32GB 1600MHz DDR3 from OWC for =+$200.
3TB 7200rpm Fusion Drive
NVIDIA GeForce GTX 680MX Graphic processor with 2GB of GDDR5 memory
AppleCare Protection Plan
Samsung SE-506AB Slim Portable Blu-ray Writer =+$89.
Just a Guess like every one Else. The 768GB SSD may bring it over $4000.
To get the NVIDIA GeForce GTX 680MX Graphic processor with 2GB of GDDR5 memory you have to get a 27" 3.4GHz quad-core Intel core I7 with 8MB L3 cache or 3.2GHz quad-core Intel core I5 and if you getting all that you should upgrade the Memory to 32GB from either Crucial $160 or OWC $200. If you get the 1T fusion you might be able to knock off $200 or so. But I think it will cost over $3000.00
Sorry