:'(Seriously some noobie statements  in this discussion.

1. FPGA  is NOT , I repeat NOT a single product from a single manufacturer and as such there are NO hard and fast rules on what you can and cannot do with  BRAMs or memory generation, even the Xilinx product range has a different 'flavour' across product lines.

So statements such as "you don't know what you are talking about" only show you up for the noob you are, if you were THAT WELL researched you would know this.

Talking about 'RAM' as a single entity is also a misnomer ,because generally there are multiple ways to 'construct' RAM, which is after all just a flipflop.

If you are "lucky" the FPGA may have BRAM blocks where the internal resources and routing are all optimized for you, and you just 'hook it up'
If you are not one of gods chosen people then you have to construct the 'RAM' from normal logic, with all the shitty routing and interconnection that infers.

2. Memory access speeds have little to do with it, ultimately it comes down to internal logic chains..., no matter how FAST your memory is,
if your shittly VHDL/verilog is so badly written it takes 20ns to execute a clocked routine, then you may as well just be using paper& pen as a scratch pad, ultimately it bottlenecks somewhere.
Xilinx allows their internal BRAM to be operated 'upto' 600Mhz on some of the V5/V6, but unless you can get the rest of your relevant logic upto that speed , it does not really matter how fast it is.

As regards Scrypt, I had actually contacted some members who claim to be interested in Technical co-op, but it came to naught....
People are only interested if they think you have an edge.

I have my own Scrypt code for Xilinx FPGA and a pluggable rack system, that takes 10 boards, I had to mux them as 8+2 hot spares.(yep sometimes they drop in & out of service randomly)

Its a nice size, about 70cm*20*35cm, which allows for cooling & to slide PCBS along to get the JTAG into each board, with per board highspeed 17CFM MAGLEV fans (none of those shitty fans with the oilpool and stupid split washer under a label)
Only oversight is WTF do I put the PSU's.....(I'd banked on an ATX actually being able to supply the 3V3 supply, but they all lie about the capability)

Unfortunately...
Performance is shite...... insofar as comparison to high-end CPU or GPUs.
Who knows if I can get an improvement but it is going to be very hard to beat the GPU thrughput Vrs cost.