I am starting to wonder if it would just be easier to take the damn gc3355's off the boards, create a new pcb that can handle the power needed for SHA and start a password cracking service 
I haven't checked, but I'm not sure they are that efficient for sha256. The dedicated sha256 chips would probably work better if they could crack passwords. Not sure they can crack passwords, even if the algorithm is the same.
Undervolting the GC3355 for scrypt will still make it usable for some time, but it's clear that ROI will be hard if you haven't hit it yet. As usual, new coins, instamining, luck... Could help.
The scrypt asic market is currently moving too fast, and prices are dropping in the same way. We should have something more stable when 28nm will be widely available. prices for hardware will level around 6-7$/MH and after that, it will only slowly decrease.
It'll be the best time to buy bare chips and build custom hardware, since the prices won't be cut by 10 or 15% every week.
The market is moving so quick that by the time you test your design, order parts, build circuit boards and then populate you might
be too far behind in hash power to get a good ROI. You would have to push the limit and go for max hash power out of the gate
with the current 28n chips in the marketplace and not be spoon fed with little increments in hash power and less watts like the
manufactures currently do. I would think it would be a greater expense, and time especially if you tried to build yourself but if you
could fork out a bit more money for a pile of chips and go and create a 500Gh+ unit or boards that can array to create a larger
hashing powered unit (Similar to old ASIC blades). The only drawback is the higher wattage need to drive the current chips that
would require you to have multiple 15A services feeding the unit unless under voltage and max amount of chips are used to help
decrease the power draw.
I have my old blade running at 1khz & 41k on my pot and getting 6.8Mhs @ 154deg on the mosfet heat sink.
Will try to crank her up a bit on the weekend and see how much freq she can take.