FocusedWolf: Good news for you, 
Code::Blocks on linux looks almost exactly to 
Anjuta (can take screenshots if you want), that's because it renders using GTK there.
BTW, if you're really interested in making C::B themeable, you should contribute a theme for the 
wxUniversal port of wxWidgets, which supports non-native themes. 
Nothing to do from the C::B side right now, except making configurable some control things like the 
color background on the 
Message/Management panels. 
Native widgets are the best for me, and here's why: the applications will look as good as the theme you choose for the OS.
If you are using 
Windows XP, just get a theme like 
FlyakiteOSX and your Code::Blocks will look like this: 

