Researcher,
You are correct. They were a dead end. Jack O'Connor insisted they were not, that the 410 evolved from them. He was incorrect.
These chamberings were only around for about 15 years. I can not locate a gun chambered for the 44-shot before 1900. Gabriel in his excellent book, "American & British 410 Shotguns" misses their importance. He also claims a Colt hand gun was chambered for them in the 1870's or 1880's. However, I can not verify his claim.
There is a belief that they were used by trick shooters in the wild west shows. This makes some sense. A solid lead projectile would eventually tear up a tent and become lethal to the audience. The usual claim was that Annie Oakley used one. This may be the case, but no gun so chambered has been traced to her. Besides she proved her skills in many actual competitions where tricked loads would have been detected.
For something very rare, a complete Ideal 44XL reloader with box:

dubbletrubble,
You are welcome. In case you are looking at one.
The prices for the single shot full side shotguns runs from $50 to about $350. For a pistol they average around $1,000 - $1,500 with the Marbles 1st version in the original wooden case with holster bringing $2,000 to $3,000. The Belgian sxs's hover around $500-$1,000, every one I have seen has needed work. For an American produced 44-shot sxs the prices start at $1,000 even in very bad condition. Here is a Harrington & Richardson 44 sxs that sold recently for just over $1,000 and it was missing the butt stock!

Pete