Virtex 7s have a bunch of different pin counts (I see devices with 1157 through 1930 pins), all BGA. You have to tell us the specific chip. Once you have a board made, you have to be able to solder a BGA, probably one with a 1000+ pin count, which means a reflow oven. Are you up to that?
The best way to approach this, IMHO, having done some things approaching this (but not on such a large part) is to find a schematic for a development board from any serious manufacturer. Base your design on that. What could go wrong at that point?
For example, I enter "virtex 7 development board" into Google and soon find this:
A development board schematic based on Virtex 5:
http://www.digilentinc.com/Data/Products/GENESYS/Genesys-sch.pdfXilinx Virtex 7 Development Board VC707 schematics, based on the 1761 pin XC7VX485T-2FFG1761C device:
http://esimioni.web.cern.ch/esimioni/files/EvalOptoMezzanine/backup/vc707_Schematic_xtp135_rev1_0.pdf
(you may want to save this, this is password protected at Xilinx and I don't think these guys are supposed to have it available on the Intertubes.)And after all of that, you will maybe be able to get the time-limited 30 day eval software you need to program it. The free version will not work. If you figure out how to get the full-feature-time-limited software to work past the 30 day limit, please tell me. It's your duty to do so since I gave you some solid pointers here.