Re: Keith's velocities.
Much of his work was done long before portable chronographs became available to the common shooter, so he estimated velocities.
My understanding is that ballistics labs that later chronographed his loads found their velocity much less than Keith reported.
Not a clue what those balloon-head .44 Special cases are worth. If they were a caliber more popular for black powder, such as .45 Long Colt or .44-40, and the cases were like-new, they might bring $1 apiece.
At least, I've seen them for sale at that price at the gun show in Salt Lake City.
But the .44 Special? Perhaps half that, or 3/4 ($25 to $35 per box of 50). But again, if only once-fired and like new.
In the end, it's all what the buyer wants to pay. Rather difficult to guess that, since prices are often regional.