About time Cadence woke up... working with large FPGAs is tough enough, but when you try to keep the PCB in-sync with the front-end, it is a long and tedious problem. I tried Mentor and had to buy I/O Designer, which worked, but still felt like a manual process. Someone told me that Altium has this as an integral part of their product and works automatically. I just completed an evaluation and I find it works perfectly. I can pinswap my Virtex II to make routing cleaner and then "magically" see the changes in the schematic. BRILLIANT!!!
So look at this new tool from 7Circuits + OrCAD + Allegro, then look at DxDesigner + I/O Designer + PADS or Expedition, then look at Altium Designer 6 - Board.
I am sure you will choose Altium. Just my two cents.