Hi piratebird
I have used a database, Chrome Princes to come up with a system that show a profit over the life of my database, around 13 years. It's a a small profit and to make it viable the bets would have to be large, but a profit nevertheless.

I haven't followed it live with money so don't know how it would go in real time, keep going or fall over. So don't now if this would qualify under your definition of a 'successful' system