Cost is not prohibitive, IMHO, for a preamp of this class, just as long as someone doesn't go wild on exotic parts and connectors.
Neutriks are just fine, for example, but I'm sure there are people who'll find them "not hi-end enough" for them.
Judging by the attenuator, I think there'll be enough interest for a GB, thus making pricing even more attractive.
Will we be able to see measurements etc of the finished product?