So I'm aware of the big ammount of general-purpose scripting languages like Ruby, Python, Perl, maybe even PHP, etc. that actually claim being usable for creating desktop applications too.
I think my question can be answered clearly

Are there actually companies using a special scripting language only to create their applications?
Are there any real advantages on creating a product in a language like Python only?
I'm not talking about the viability of those languages for web-development!
Should I stick with C(++) for desktop apps?

best regards,
lamas
The company I work for uses Perl and Tk with PerlApp to build executable packages to produce or major software application.
Perl beats C and C++ for simplicity of code.  You can do things in one line of Perl that take 20 lines of C.
We've used WxPerl for a few smaller projects.  We'd like to move fully to WxPerl, but existing code works, so the move has a low priority until Wx can give us something we need that Tk can't.
Python is popular for building GUI apps, too.  You may have heard about Chandler.  That's a big Python app.  There are many others as well.
Ruby is also a suitable choice.
PHP is breaking into the world of command line apps.  I am not sure about the power or flexibility of its GUI toolkits.
"Real" and non-embedded use of Ruby, Python and their friends