Proven succesful managers who could take over Everton? you literally want me to name a list when theres loads of good suggestions in this thread alone, you can use the google function to see their relative success or not.
With money behind you, like i said earlier can open a lot more doors.
I've already suggested Hiddink on a short term basis whilst we can assess what comes available.
I've already openly said i'd love for us to try to get Mourinho, I wouldn't even mind AVB ahead of Martinez. I'd have all of them above Benitez.
Others have suggested the former chile manager, who has had relative success, but not one i'd personally go for, others have also suggested Unai Emrey which could be a good choice.
There is also the likes of Lippi you may be able to get on a very short term deal, Jorge Jesus from sporting.
Point being there are loads of managers out there who could be a success.