Eh, not that surprising: you don't need to register a tractor the way you do a car, so there's no central registry of what tractors are still being used.
Re: energy storage, oof, yeah, at 146.5 MJ / gallon for diesel fuel, and 10 gallons / hour, 12 hours of fuel holds 4884 kWh of energy. Assuming you need a similarly sized battery, you're looking at 60 Tesla (car) batteries. That will weigh approximately 36 tons and cost about $700,000, based on Tesla's 141$/kWh stated cost.
Hmmm, I'm guessing you can't put more than 8-10 tons of battery on a tractor that size (the John Deere 7250, which is actually 13g/hr, weighs 13 tons) so you're limited to maybe 3 hours or so of power between charges or swapping out your batteries. For that much battery, you're looking at maybe $175,000; the John Deere 7250 retailed for ~$230,000. Assuming your batteries are swappable and fast-chargeable, you'd need at least two batteries. (Heck, it's a tractor, maybe it can be on some sort of wagon you tow behind, which would make swapping a snap.)
Putting it together, I think we might actually be approaching viability for electric tractors. If you can actually fit 8-10 tons of battery into a 13 ton tractor and build the rest of the tractor for $55,000, you could build a tractor comparable to the John Deere 7250 that would run for about 3 hours; that's not a bad amount of time to run between swapping out the batteries, but you'd need at least another $175,000 battery to swap out, which already makes you ~twice as expensive as a regular tractor. You would probably need the battery weight and cost to drop by half again before you could get a tractor that would run all day (with a battery swap) and not cost more than a conventional tractor.