I think that the idea itself pureh@te is good and your intentions with it are good as well. But I think that as cybrsnpr mentioned the Non-Disclosure Agreement may be a big hindrance of using this in an actual paid pentest.
The data would/could be considered proprietary. As such companies may not want their hashes being uploaded someplace outside of their control.
As an example I am not allowed to store anything "government" on my company laptop but I can access it all I need/want to. The servers that hold the data are controlled by a third party (CSC in this case). Now the only reason for this is due to non-disclosure agreements. If I lose the laptop for some reason I don't have a lot of secret whatever that can get me in trouble ( the laptop itself is a different story). This keeps the company and the Government "clean"
I am wondering how you could ensure that the data you have is not stored and can not be re-accessed.