What is the strongest FPGA right now which is deliverable?
The hype about ASICs last year pretty much killed the market for FPGAs, everybody went and preordered ASICs so the custom FPGA boards dropped off the market, also helped by the fact that Avalon (Lancelot by ngzhang) and BFL were the major suppliers of FPGA at the time and dropped their FPGA products. It just did not make sense to buy them at $10 to the
BTC when ASIC was promised so very soon. Fast forward to $100 plus
BTC and just a trickle of ASIC and
everybody newbies want in again.
If you can't get a Lancelot or Enterpoint. then perhaps one of the (expensive) Kintex dev boards they are talking about on
https://bitcointalk.org/index.php?topic=9047.0 but I can't vouch for the ROI.
The custom hardware thread is a good place to look, but its mostly ASIC these days
https://bitcointalk.org/index.php?board=76.0