I actually wish you all the best if you plan to build one. Having said that, you are identifying a niche product which can only survive by charging people money for searching, which more or less caps how ambitious such an idea could be.
I've always suspected it should be possible to charge people in non-monetary ways. That is to say: charge them by having them give you computer resources.
You've still got to monitize those resources though. I think an enterprise subscription model could work well. It could increase productivity.