Just to through some more ideas in the pot (couldn't resist...):

Full size images derived from Timo Schoeler's first draft:
http://www.3tb.de/netbsd/pkgsrc-logo-grey.png
http://www.3tb.de/netbsd/pkgsrc-logo-white.png
http://www.3tb.de/netbsd/pkgsrc-logo-mono.png
http://www.3tb.de/netbsd/pkgsrc-logo-outline.png

Scaled down versions of the above:
http://www.3tb.de/netbsd/pkgsrc-logo-grey-150.png
http://www.3tb.de/netbsd/pkgsrc-logo-white-150.png
http://www.3tb.de/netbsd/pkgsrc-logo-mono-150.png
http://www.3tb.de/netbsd/pkgsrc-logo-outline-150.png

Regards,
Tom