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In all seriousness, that looks pretty amazing.
edit: there's a mini interview w/ him over on that other site. he mentioned his first mountain bike was a norco.
As for large pulleys, the larger the better - the larger the pulley, the slower the bearing rotates as drag in bearings increases with rotational speeds increasing. Plus, the larger the pulley, the less chain links rotate and thus cause less frictional losses.
There's a reason Protour teams supported by Sram pushed for an 11-x cassette with standard front rings as opposed to the 10-x cassettes, that enabled Sram to use smaller front rings, the 10T is so small, the losses increase and you're closer to the polygon effect rearing up its ugly head.
As for bearing losses, bike drivetrain rotational speeds are somewhat low, though with road bikes, if you're pedalling at 90 rpm in the 50-ish tooth front chainring, the 10-ish derailleur pulley will rotate at ~5-times the rotational speed of the cranks. So at roughly 400 to 500 rpm. And that's not that low anymore. With mountainbikes we're at more of a 2 to 3 ratio (30-ish teeth on the front chainring, 10 to 15 tooth pulley gears), so we're in the 250-300 rpm range. Increase that to a 20T pulley and you're in the 125 to 150-ish range.