I found an awesome looking, dark theme to Samsung Galaxy Spica i5700! I don’t know what to say else than it’s just awesome.
But the latest version (8.1) requires that you have a Spica phone running the custom ROM Samdroid v1.2.x or 1.3.1 deodexed. And to run Samdroid you must root your phone with the LK kernel. I only recommend doing these steps if you know what you are doing and are aware of the possible damages.