Time to write something. So, 1.2.2 is out, it's time to update this awesome faithful mod! TheFrogMC, have you got some new ideas about furnaces? It is not very funny to update this topic every day and see no updates.
So, finally, a wild new post appears.
I'm waiting for this mod to be updated as well, this mod actually makes a good use for the tons of iron I have and for gold. All of my worlds have at least a couple of these furnaces and I don't want to lose them =P
As others have said, perhaps a furnace with more storage, or one which will smelt everything in a chest and depost ingots in another.
Also, instead of adding more types why not add features to existing furnaces like being able to burn more objects in the game as fuel, or perhaps if a furnace is above natural lava it doesn't need a fuel (or a special furnace which has this property)