@t-nelson: I think you'd find plenty of people willing to trust a completely new, closed source miner, as long as it was published/developed by a trustworthy person. That is the case with Claymore's Cryptonight miners for example.

It so happens that not a single person has shown interest in developing such a miner for the Nvidia crowd.
It is obviously (a lot of) hard work, and not certain to ever be worthwhile for the developer venturing on this. There's also various limitations of technical nature that result from a fee based approach, but not worth getting into that discussion, if we can't even get past the interest stage.

Wolf0 had been doing something of the sort (own miner developed from scratch). Maybe he can share his experience on this, and we'd get the point of view from someone on that side of the fence, someone that actually spent some time on a similar project.