I think a lot of the value one gets from researching the reporters/journalists/bloggers is getting to know their content and getting a sense of the "personality" of each publication, not just finding contact information. That being said, it sounds like your service would allow people to focus on the important stuff and make it simple to contact whichever people you select (while many journalists make their contact information readily available, there are those that are more difficult).

I wonder about the legal issues surrounding this idea. Last time I worked with a service that provided an email database and sent people emails, it required an opt-out link in each message -- which would be easy -- and it required prior opt-in from the person being emailed -- which would make it a bit harder for you. I was working in market research then (a few years ago), however, and the laws and regulations may be different.

Anyway, certainly this is an idea worth looking into, I hope you go for it and have great success!