IANAL and I am not familiar with Eiffel, however I am reasonably sure their statement, "The GPL version is for the purpose of developing open-source software only! If you want to evaluate EiffelStudio for commercial software development, please download our Enterprise Evaluation Edition", is a violation of the GPL. The GPL FAQ states that the output of a GPLed program retains the same copyright as it's input:
Can I use GPL-covered editors such as
GNU Emacs to develop non-free
programs? Can I use GPL-covered tools
such as GCC to compile them?
Yes,
because the copyright on the editors
and tools does not cover the code you
write. Using them does not place any
restrictions, legally, on the license
you use for your code.
Some programs copy parts of themselves
into the output for technical
reasons—for example, Bison copies a
standard parser program into its
output file. In such cases, the copied
text in the output is covered by the
same license that covers it in the
source code. Meanwhile, the part of
the output which is derived from the
program's input inherits the copyright
status of the input.
As it happens, Bison can also be used
to develop non-free programs. This is
because we decided to explicitly
permit the use of the Bison standard
parser program in Bison output files
without restriction. We made the
decision because there were other
tools comparable to Bison which
already permitted use for non-free
programs.
This says to me that the code produced by the GPL version of eiffelstudio need not be released under the GPL.
Here's a few more for you:
Is there some way that I can GPL the
output people get from use of my
program? For example, if my program is
used to develop hardware designs, can
I require that these designs must be
free?
In general this is legally
impossible; copyright law does not
give you any say in the use of the
output people make from their data
using your program. If the user uses
your program to enter or convert his
own data, the copyright on the output
belongs to him, not you. More
generally, when a program translates
its input into some other form, the
copyright status of the output
inherits that of the input it was
generated from.
So the only way you have a say in the
use of the output is if substantial
parts of the output are copied (more
or less) from text in your program.
For instance, part of the output of
Bison (see above) would be covered by
the GNU GPL, if we had not made an
exception in this specific case.
You could artificially make a program
copy certain text into its output even
if there is no technical reason to do
so. But if that copied text serves no
practical purpose, the user could
simply delete that text from the
output and use only the rest. Then he
would not have to obey the conditions
on redistribution of the copied text.
In what cases is the output of a GPL
program covered by the GPL too?
Only
when the program copies part of itself
into the output.