COMMENT: At the moment the Church of England expects their non-stipendary (self-supporting) priests to work for nothing AND give any money they earn from funerals etc. straight to the diocese. House for duty priests work ridiculous hours for a roof over their head worth far less than the stipend they would be paid for the hours they put in if they were on a stipend.
My suggestion is, that in certain circumstances, the money raised by the church the self-supporting priest is attached to should go to the priest and not the diocese up to the level of a full stipend. This would encourage new ways of being church and new ways of being a priest. Both the congregation and the priest would have incentive. Not just financial but also the "lets be successful just to spite them" sort of incentive.