Re: how much is too much?

[Alfred M. Szmidt]

Just to clarify to the Original Poster.

   GPLed code is not convertible into other licenses, but that does
   not mean that other code is convertible to the GPL.  There are
   actually very few licenses that allow rereleasing as GPL.

And lets not confuse relicensing with rereleasing.  The former
requireing the copyright holders permission, the later whatever the
license says.  So if you rerelease some BSD licensed code under the
GPL (without making any modifications, to make things simple), you
can't remove the BSD copyright notice, since the work is still
licensed under original license.  Compare this with Public Domain,
which would allow you to do what ever you wish.