well, the fabled tortoise technically has a higher capacity.
of course, if multiple people wear a hoplite, it will surpass it.
and i don't think the hoplite slows you down as much if only one person is wearing it.
The Hoplite lists lower capacity on the item card, but the 20% bonus applies with even 1 in the party, so it is actually stronger than the Fabled Tortoise, even solo. Of course, it has a larger health penalty, but no movement speed penalty unless 2 or more people are wearing one.
The Hoplite's Capacity isn't that much worse than the Tortoise anyway. there was about 20k in it at level 50 according to the item cards but the Hoplite gets a capacity boost from its effect even if just you are using it.
I like the Hoplite though because the movement speed penalty is fairly small if no one else has one.
As for the max capacity at 61. With full pangolin parts based off of the level 50 stats with the standard 13% per level increase you would be looking at 618,553 capacity on the item card give or take a point or two