[Koha] ItemType icons and "biblio vs biblioitems" revisited (sorry)

[hansbkk at gmail.com]

I'd really like my Item Type to be able to display an icon right on
the search result, without having the member having to drill down to
the detail page. In searching on this issue, I see discussions about
the little icons associated with the MARC leader - don't think I want
to go there.

And a whole lotta talk about "biblio level" vs "biblioitem level"
fields. Which has got me very confused, because a few years back when
I was first exploring Koha, I was told that this distinction was a
leftover from pre-MARC database design, and that now these are
functionally a single table with 1:1 links between them. Here's a more
recent explicit statement:
http://lists.katipo.co.nz/public/koha/2009-December/021641.html

Has this changed with later releases and there is now a one:many link
between a biblio record and many bibioitems? If not, then I don't see
why the ability to display an icon on the search results should depend
on which (part of) the record it's in?

I see there is a preference as to which table's itemtype to use,
between biblioitems's itemype or items' itype - is that relevant and
even if not why would I choose one over the other?

My current use case is that I have multiple media types for a single
film. It's all exactly the same video, not a different edition, but
one might be a disc that's playable on a consumer player (Disc-Video),
another may contain computer files (Disc-Data), another combines both
(Disc-Mixed), some of our VHS tapes haven't been converted yet, and
some really old home movies are even on 35mm!

It seems to me that I must catalog these as separate biblios, which
creates multiple identical copies of the biblio-level MARC data, and
just different ("holdings level") data in the items table, including
item type. So when a patron searches for "2009 Proms Gala" they will
get four identical but separate results. How can I indicate the
different item types right there without them having to go back and
forth between the search results and the detail screen? Ideally with a
configable icon, but plain text would be OK. Worse case scenario I
could use re-purpose "shelving location"? (yech)

Note that I'm going to enable Collection rather than ItemType as a
factor in advanced searching; I'm just looking for the ItemType to
display in the search results.

A related question - is there a way to bulk update the "biblio" level
information for all four of these separate records in a single
operation?