Cels are not novelty items. They either can be 
considered artwork or industrial waste depending 
if you are collector or a person working at the 
studio. For us they are artwork, since they are 
unique graphic interpretation of a subject or a 
situation. For studio's they are industrial waste 
that can either be sold to subsidize the cost of 
production or destroyed if they are not willing to 
release them or if their advertisers will not 
allow them to be sold.

Except in a few very rair case, almost all cels on 
the market were released by the studio as gifts or 
by being sold. While this does not give you the 
rights to the characters, you do have the right to 
own the cel. Even Disney who obsessive with going 
after people infringing on their copy righted 
characters cannot stop someone from owning or 
selling a cel depicting one of their characters. 
In addition, while you are quick to dismiss Hanken 
Mono cels as illegal, they are the most legitimate 
cel of any of them, since their sale price usually 
include licencing rights for that image. This is 
in part why their cost is so high.

Anything which is subject to fluxuation in prices 
as result of public demand is an investment. For 
this reason, when cels are insured properly, they 
are replaced at the cost that a reasonable person 
on the current market would pay for that image. By 
your logic, no artwork is insurable at any level 
beyond what you paid for it.

Cataloging is only significant for items that are 
of substantial value and is to insure the fakes 
are not entered into the market. This is the main 
reason that broad catalogs of artist works are 
made. It may come to pass someday that cels will 
reach a high enough value that they will be 
cataloged and recorded, but at this time it is not 
necessary. 

Insurances require item above a set value 
(1,000-5,000) to be individually documented, but 
items below that value are also insurable. They, 
however, are usually covered by a blanket art 
rider that will require documentation of your 
pocession of the item only if a claim is made. 
By your assertion, no collectable under 1000 is 
insurable because it is not worth enough.

If you want to get back to me on any points feel 
free to contact me privitately and I will break 
out my tort law and insurance policy books.

Catch you later,
Marcus