I think with enough repeaters you could create a lava redstone refill system haha.

you can only have 1 furnace and only use it by yourself. other people cant place lava in it. I would make more then 1 but i dont have enough magic x.x Lets go to Hoghwarts and ask for Jallaf the wizzard...

Having only one isn't so bad. 512 uses per bucket of lava, while keeping the bucket, is totally worth it (in terms of resource efficiency).

However I do get slightly disappointed every time I go to check it; the double chests I placed on each side, while extremely high in capacity, would take (64 * 9 * 6 * 10 / 60 / 60) 9 hours 36 minutes and 7 buckets of lava to complete.

I wonder if they keep the chunk they're in loaded; if I have to be in my house to keep the lava furnace running, I might opt for a 27-furnace wall instead. Redefining "parallel processing" all UP in this. (Coal and blaze rods are renewable resources, too, so technically this is the more "eco-friendly" option.

More statistics:

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• One bucket of lava keeps a furnace going for 512 10-second smelts; 5120 seconds is 85 minutes, 20 seconds, or just short of an hour and a half.
  
• You could smelt a double chest full of things in around a ten-hour session, taking into account refilling the furnace periodically. Probably best you don't try this in one sitting.
  

This makes me wonder: how hard would it be to modify the plugin to accommodate a third chest for automatically-used fuel?

Oh man, the alternative setups would rock!