Have a look at Revolution from Runtime Revolution - it is a cross-
platform IDE that can build executables for each platform from exactly
the same code. The IDE is itself written in and runs within the
same 'virtual machine' that your executable will run in. There
are 'virtual machines' for OS X, OS 9, Win32, Linux, Sparc, Irix, AIX...

You can produce royalty-free binary executables, or even scripts.

It is descended from a version of Hypercard that was originally written
to implement Hypercard on unix. It is commercial, but starts at
something like $99 for a single platform (and the most expensive version
is $1000). The code is very readable (just about the most English-like
code you will ever come across). It is another world from coding in
Delphi or C++ or Java - in fact, it is a lot easier than VB.

You would have to access Firebird via ODBC though...

http://www.runrev.com