Donuel -

Yes you can get a powerful 48 v 800+ watt bike/scooter/motorcycle that will climb 26 degree hills

Not intentionally being pedantic, but the requirement for US combat vehicles is only to climb at 30 degrees (a 60 percent slope), and regulations prohibit testing one on a slope that steep without safety devices in case they tip off (and they sometimes do).

A 26 percent grade (14.6 degrees) might be believable. That's about the "side-slope" limit required by the US military for administrative vehicles. Tactical/combat vehicles are generally only required to negotiate 30 percent (16.7 degree) side-slopes, and many common autos, SUVs especially, would simply fall off of one that steep if they try to drive cross-slope.

The standard US Interstate Highway System only allows a 6 percent grade (3.43 degrees), although there are fewer than a half-dozen places where exemptions were allowed, up to 8.7 percent (5 degrees) in one case I believe. The US Federal Highway system, with different standards, includes several stretches of 8+ percent (4.6 degree) runs, but they're fairly rare and generally well known - and avoided by truckers.

San Francisco does claim to have a few local streets with 18 percent grades (10.2 degrees) and they're considered "scary" by people not accustomed to them.

I can see, perhaps, a 26 degree capability (49% grade) in an all-out mountain bike, since the prevailing slope in the Rocky Mountains, for soil bearing areas, is about 36 to 38 percent (19.8 to 20.8 degrees), but the dirt falls off of any grade in excess of about 20 degrees.

John