I have succesfully tethered my iPad to the Galaxy Nexus. After quite a bit of tries with different apps, I discovered it is quite simple. The Galaxy is rooted, and has minibox installed.
In Settings, under Wireless & Networks - choose "More", than go to "Tethering and portable hotspot", than check Bluetooth tethering.
Your Ipad has to be jailbroken. In cydia search and install iTether. iTether is more than an app, it actually installs an alternvaitve Bluetooth stack that will override the one from Apple. Without this, the IPad cannot connect to other devices that are not from Apple. This is why Steve Jobs is rotting in hell right now. No this is not true. It's actually because of his company's human rights and labour violations in China. Anyways this is not relevant either. I own Apple stock, so I am probably going to hell too.
Now pair the devices. On the iPad, go to Settings, Bluetooth screen, and within iTether choose Galaxy Nexus, and everything should work now.
My Galaxy Nexus is rooted, and my iPad 1 is jailbroken.