Blackberry themes for different blackberry models can be found here:

Guideline to BUILD YOUR OWN BlackBerry Themes

Blackberry 7100 : find all themes for your blackberry 7100 here

Blackberry 7200 - 7500 :all themes for categories between the 7200 and the 7500

Blackberry 8100 Pearl themes: here you can find different themes for the blackberry 8100

Blackberry 8300 themes: all themes for the blackberry 8300 series

Blackberry 8700 - 8707 themes: find different themes for your 87xx series

Blackberry 8800 - 8830 themes