I am thinking that FPGA has not been explored enough.
Maybee there are some that can be used to mine different crypto-currencies at a decent rate with low power-consumption and low unit-price compared to CPU based mining riggs.
It truly hasn't. I'm still working on a FPGA project of my own, very very slowly. But developing the bitstream for multiple currencies is possible with FPGA's. If LTC becomes huge once the ASIC's hit the market bit time, FPGA's will be back in the game.