I know you don't want to hear about it, but Runecrafting double nats is (according to what I've read) the best moneymaking method. Consistent profit. No dependence on whether you get the good drop. Put 15 minutes of time in you get exactly 1/4 of your hourly profit. Put 16 hours in you get 16x your hourly profit. Not dependent on other people. Good profit even when laggy.
After Runecrafting double nats, merchanting is the strongest moneymaker. With a little effort you can set up a system of trades that bring in a surprising amount of money. The only reason Runecrafting beats it out is because there is always the possibility of losing money. Generally if you are a successful trader you can make considerably more money per hour invested than any other method. Just take your lumps when you lose money!
High level imp catching. No loss here, and solid strong profits. But because it depends upon random drops it isn't as highly rated as runecrafting. Still, hunt imps for a few hours and you WILL consistantly make good money.
Finally, my notes say that most high level players with good combat skills make better than 800k/hr profit by:
Daggonoth Kings. With the occasional rare drop of 4 million, the average is somewhere around 800k/hr.
God Wars team coinshare reportedly is 4.7 million/hr Saradomin, 6.7 million/hr Armadyl
Almost any boss monster. KBD. Ggraardor. Krill. Get on a team for the Corp. Beast.
Depending on market value, 800k/hr is possible by running Bones to Peaches tabs in your house.
That's what my notes say. Some of this may be a little out of date.