I had a question about themes. I just got a 8520 for my gf and she is dying for a new theme. I searched Crackberry for free themes for the phone but have not found anything yet. I understand that themes are OS specific so i tried an iberry theme I found in the 8900 forums. It shows up in the application list but not in the themes list.
You answered your own question. Themes are made and only going to work on the specific device they were created for. Give it a few weeks as the 8520 was just released and I am sure people will start cranking themes out for it.