Perhaps a second hand SP50!?
Have to find a NEW SP50 around somewhere first - so far as anyone knows outside of Spondoolies themselves or possibly someone under NDA, they seem to not be in existance or production yet.
There has been NO announcement on price on the things anywhere public that I'm aware of (I've looked), just quite a bit of speculative guessing.
While 7 cents/KWH (US) is fairly cheap, it's not VERY cheap or even close. 5.54 is getting close to the VERY cheap range, but definitly is not VERY VERY cheap 3 cent/KWH or less like most of the major farms seem to have access to - and if you expect to be profitable for the long term you've got to get at least fairly close to their ballpark.