what would be the best FPGA rig for around 2k - 3k
Maybe you've not been following closely but ASICMiner is up and running and will themselves be massively increasing the THash/s. Avalon ASIC has shipped a few units and will be shipping in quantity soon. BFL says their stuff is coming along.
Why blow $2k - $3k on FPGA now? It's over. Go home.