> I don't know how modular ICU/C is with regard to transcoding tables.

FB is linked dynamically.

> However, even then, given new Delphi projects spent half-MB just for
> an icon, i would not think 2-3 MB more would be a barrier.

That's not, but the directory layout on the file system. Are you
prepared instead of simple fbclient.dll to ship firebird.cfg,
bin/icu*.dll, probably intl/ directory and some more?

> There are still plenty of users stabilized at D5/D7 or D2006
> I am working at XE2 now, but people around me work at D2006 and the
> place i was interviewed before had stock stock-keeping framework
> written in D5 (which was my D version of choice before XE/XE2).
>
>
> In D2009+ you have language-default "string" made UTF-16
>
> (http://objectmix.com/delphi/722660-unicodestring-utf16-variable-length-ucs-2-fixed-size.html),

In Java a string is a class, objects of which contain sequence of
characters, a character is a 16-bit value that can be casted to int.
They are UTF-16.

You can construct a string from byte array, but you have to specify the
encoding for the byte array (or it will take the platform's default).
You can get bytes from the string, but you have to specify encoding, in
which you want them (or it will take platform's default).

Roman