iPad Pages: replacing the wood effect theme
If your device is jailbroken, I assume you can modify files within an app's bundle? I haven't jailbroken my device, so I'm not sure exactly how this works. However, if you have:

Within the Pages bundle, there are images called TP_RulerBackground.png and TP_toolbar_top_bg_norm.png. If you replace these files with something else, it'll change the toolbars/rulers.