Those are all strong because of their basic design, but almost all are made from weak steel and aluminum. Some of them are weakened by being made especially long for chopper bikes. The pedicab shop I work with replaced all the legs of their triple clamp forks with legs specially manufactured from thicker-walled seamless chromoly steel.
I suppose I'd trust the ones sold by Main Street Pedicabs over the usual lowrider and chopper stuff, because they are time-tested in a heavy duty application. Still, I have seen a whole bunch of those bent beyond repair.
Use the threadless kind, with a corresponding threadless headset and stem. Use only as much extension of the fork as you need to clear the tire.
Note that many forks of this type are made with 135mm width, as opposed to 100mm width for typical forks. If you use the wide kind, you can put a rear hub motor in the front. But in any case, get the kind that works with the front wheel you want to use.