I've synched several iPads and other iDevices to the same iTunes account by backing up an older one, then using the "restore as" feature when synching the new one. Once the new one is hooked up for the first time, I just change the device's name and manually toggle off anything I don't want synched in future.
That's worked fine over the year+ I've used iPads. iTunes automatically remembers each device and its profile whenever I hook up via USB, and what's already offered via cloud is already working on each device. Backups work fine, too.
I also set up and synch my husband's iPad the same way, to my account.