Thomas,

> is anybody in the business to recommend a RAD tool for creating
> database-driven web applications without having to much
> language-specific knowledge, e.g. hand-coding stuff with PHP etc.
> from scratch?

Morfik is very Firebird (and Delphi) friendly but it is very basic when
it comes to data-driven applications. At my company, we have built our
own to generate standard data-access forms from external metadata.

A good and advanced tool is also IronSpeed, but it's not really
Firebird-friendly.

There are lots of half-baked solutions out there; you might want to have
a look here:

http://en.wikipedia.org/wiki/Comparison_of_web_application_frameworks

HTH
--
Nando Dessena