Hi Marcus The Antenna-Rich,
the GR logo is Creative Commons Attribution (No derivatives) license.
Which means that if you did come up with your own design based on
modifying / building on that logo, you'd not allowed to distribute it
(without asking. and with you, it'd be probably totally OK, so, don't
worry.)
It's pretty clear to me that your front panel design simply *uses* the
logo, exactly how it's meant to be used: as a sign that something
contains, uses or is related to GNU Radio. So, this is clearly the most
desirable usage, and you're absolutely free (and the license guarantees
you are) to use the logo. It's not a "derivative". I'm not a lawyer,
obviously, and Ben would probably be able to comment more qualifiedly
than I am, but I can put in my full confidence and say: We'll never
stop people from using the logo to denote usage of the thing it stands
for. That'd be against the idea of *having* a logo in the first place.