Hey Sean, I have thought up what I think is a potentially very lucrative idea for a website, filling a need I can't find anyone else filling. Is there a realistic route to finding a way to market it to a company or is that just a pipe dream?
I'm not sure I fully understand the question.
If you are asking if there is a realistic way to introduce your idea to a company, in the hopes that they'll also think it's a lucrative idea, and go build the website, cutting you into some of the lucrative revenue, then yes... it's just a pipe dream.
Here's why. As the "owner" of this lucrative idea, you'd want to find a company that's likely to execute on the idea well. That means you want a company with a proven track record in the general market area of your idea. You'd also want an NDA with the company to protect yourself from them taking your idea and executing on it without including you. Now... the company can't be sure that they haven't already thought up your idea, so why would they ever sign your NDA for this, opening themselves up to a lawsuit from you for something they've already thought of?
Any company that would entertain this is not sophisticated enough to execute on the idea.
If you really think it's such a lucrative idea, pitch it to venture capitalists and angel funders and see if they think it's a great idea. If they do, they'll give you money to start a company to execute on the idea. If they think it's really the greatest thing they've ever heard, and you aren't interested in starting a company, they'll get one of their entrepreneurs in residence to start the company.
Chances are your idea is not actually that great or lucrative. See Paul Graham's "Black Swan Farming" (http://paulgraham.com/swan.html) and my reply, "Paul Graham is Wrong" (https://medium.com/@snootymonkey/paul-graham-is-wrong-411fe084a7da). Does your idea seem either bad or too good to be true? If not, chances are it's not that great as an idea for a new lucrative business.
Maybe I completely misunderstood your question though!