OK, you've shamed me into taking another look at it
I did the original port back at the end of October, and other than the rather low FMAX (100Mhz), it looks to be OK. It should be fairly easy (for ISE values of easy, which means much actual frustration) to push this up towards the 150Mhz or so that the other ports run at (corresponding to overclocks of around 200MHz+). There are some issues with queuing of the golden nonces (I took out the FIFO in trying to get it to actually work, hence the "robust" in the name of the port), but that shouldn't make too much difference.
The main problem is the lack of a driver in cgminer. I do have hacked up versions of the original bitcoin X6500 miner and MPBM forked on my github, but these are only going to work for solo mining, or perhaps on BlueDragon's pool if getwork is available. I suggest you give it a try with these, and if its looking OK, then I'll see what I can do for a faster build. I'd really like to know the pool-reported hashrate so as to gauge what sort of improvement to aim for.
Its going to be nigh-on impossible to write a driver for cgminer without a device to experiment with, so perhaps someone else can take a look at this instead. BFGminer appears to have a driver, so perhaps this would be a good starting point.
