Well, it seems we are all looking for the same answers. The main question to me would be which quivers can be worn in ammo-slot. The Thunderhoof quiver should be able to be put in that slot, but I have the same experience as some others: Mr. Kroldir Thunderhoof seems to be a very rare spawn, or we just don't know how to trigger him into appearing.
My opinion is that, since you wear the ammo i.e. the arrows in the ammo slot, all quivers should fit in there. The quiver should be able to contain throwing material as well (perhaps it can, I never tried this).
Anyway, I will take a deeper look into this. Maybe I can find some more answers. I did quest the 35% weight reduction Jeweled Quiver of the Hand (recommended if you don't have a quiver and you are around level 40 and you want one; it is to be obtained reasonably easily). But, it can't be worn in ammo slot and it is (of course) no drop.
Note: the fleeting quiver doesn't fit in the ammo slot either. A small joy however is that it is really really fast. Goodness gracious, great .....
Edited, Tue Nov 26 13:54:59 2002