How to choose right FPGA/board

I got a question from a collegue of mine to which I couldn't give an answer.

He asked me how to determine the FPGA of board to use before you have any board in your hands to test your code on. The emulator provides functional emulation, but is not a reference for performance. I could compile for all candidate boards and compare timing and utilization reports, but that takes a lot of time and how much does that say about the boards?

How do you do this and what should I look for?

[edit]Let's assume I can get/have the BSPs etc.[/edit]