**note: it negates the x3 all together as there is only space for 1 ingot to be placed over so as the furnace reaches 64 ingots a hopper takes giving room for only 1 more ingot making the x3 luck multiplier irrelevant.

I would personally be more interested into SF variations of Hoppers which withdraw a larger amount simultaneously (instead 1 at a time, 2 or 3 for example). Changing the movement speed is most likely of the table as I believe it's currently the main nerf on the hopper, for performance boosting.
The SF basic cargo mechanism for furnaces would be hard to achieve and would require an action most likely at the SF Devs, although it could also be applied to the Basic version of the Kitchen which is the only basic SF machine without said mechanism.

*off the table

I think an SF addon (existing or not) for buffing hoppers up is a great idea, although it would have to be limited to some extent.

Easy way to solve this, use a hopper minecart underneath instead of a hopper, then feed that into two or more hoppers via aligning the minecart against a fence or other non full block and making it so you effectively have 4 hoppers on one furnace.


An actual problem however is the input being too slow which does need to be solved, carbonado furnaces are currently near worthless because of this

That won't make a difference because it's an problem at the removal of the furnace products and not the removal of the items on the hoppers.