I have used Dektol 1:3, 1:2 and 1:1 right now, but that is not to say that D76 could not be used. I just keep Dektol around for standard testing and use that by habit.
I have used other developers to good effect, but right now Dektol 1:3 for 3' looks like a good film develper to me.
There is no reason that a silver positive could not be made with appropriate processing. I would use D19 or D8 or D11 (a high contrast developer) for the first developer and then a non-rehal bleach, a clear and redevelopment in the light, just as in a conventional process.
I have no intention of producing a direct reversal emulsion however. This is an emulsion that gives a reversal image directly from a single development step.