Hi Roy,
No. I've investigated hydronic a bit. Unless my water heater dies and I can "upgrade" to one that uses heat from the engine.
As soon as you draw heat from the water heater--the electric element would "kick in" so there is no real savings by going hydronic--other than avoiding the power draw from the furnace fan.
There would be a "convenience" factor of always having hot water "on tap". I could place the heat exchanger where the fan that replaces the furnace grill could distribute the heat.
I think the efficiencies running propane in the furnace and water heater are pretty much the same.