UPDATE
hi, I have made a new theme thats working with others two opensource apps:
Blender 2.5 series have a dark gray ui and gimp have a theme named proapp (that be acessible in preferences panel). This theme for inkscape is like proapp theme for gimp. Uses the same tango set of icons, colors and plus a new icon for inkscape.

See how the apps will look under mac os x:


For now i have update the theme for the new Inkscape 0.48.

download Inkscape 048 for snowleopard mac os x:
http://www.megaupload.com/?d=ZLPG9N3U

download the design files for inkscape with the new theme and use it free of charge:
http://www.megaupload.com/?d=7DWU815W

PLUS, I have made a package with a new icon and splash screen for Gimp too, that works with the inkscape above. NOTE: you need to set in Gimp preferences the theme PROAPP to apps working with the same look.

download Gimp 2.6.10 for snowleopard mac os x:
http://www.megaupload.com/?d=LM08T511

download the design files for inkscape with the new icon and splash screen and use it free of charge:
http://www.megaupload.com/?d=Y40MX3ED

Enjoy! Thanks all!
Vanheber

This is awesome - thanks for doing this!

All the inkscape themes you have presented here look very trendy and cool. I really would love to add them into my collections. However, there is one thing that I would like to suggest here and that is the addition of other environmental backgrounds such as wild animals, birds and other natural beauties as well which would definitely look great for the graphical user interface of any operating system, let alone MAC!
Brown | Vcloud

The target is do a coherence between Inkscape, Gimp and Blender inside Mac OSX. Of course, they can be more warm with your suggestion. But, the time to do this is very short. See the Adobe icons and splash, are very cold because needs to transmit a professional and robust app. I think that these settings have the same idea, a little, of course!

I just downloaded the Inkscape theme but how do I add it to my app?