Since I exited my last company, I spend a lot of time researching hundreds of options for passive income.

In my opinion, this is not the time in the business cycle to be making a large long-term investment in the stock market.
http://www.economist.com/news/united-states/21612168-weighing-evidence-how-long-will-expansion-last

Normally, municipal bonds are one of the best ways to create passive income because they are super safe and tax-free. However, too many investors have fled stocks with exactly the same idea, and so the prices on municipal bonds are now too high, causing their yields to go down to record low levels (which is very bad for getting a good return on them).

Personally,I would recommend taking a look at nontraditional investments. Peer to peer lending currently returns me just above 9%. This is a riskier investment because it is not FDIC protected, and if the borrower defaults then you lose your money. I reduce the risk with diversification. If I invested all my money in a single note, it's way too risky because a single default would wipe it all out. However, by spreading my money out across hundreds of notes and only buying a small portion of them, It tremendously reduces the risk. If you check out LendingClub.com, you'll see more information on this technique. (To date, no one who has diversified across 400 notes has ever lost money on the platform)

Good luck on achieving your goal!