Why are you fed up with changing the chain? Why do you think that going to an internally geared hub is going to keep you from having to change a chain in the future? How about the derailleur, why is it needing changed?

If you have a Sirrus with an 8 speed drivetrain then with proper maint you should be able to get 5k Km out of the chain easy and I think with proper care that isn't out of the question for a 9 speed either...now with the internally geared hub you could use a bit wider chain for more durability.

But that said...you want to go this route and that is you choice...how about a new frame? You could go with the singulator but I wonder if it would last under conditions that are eating chains and derailleurs. By going to a frame with horizontal dropouts you could eliminate the need for the singulator. You could probably drop in a Surly Crosscheck pretty easy.