Shouldn't Siri be able to run on the new iPad?
The short answer is no, not yet. The long answer is because the only (reliable/legal) way to get Siri on a non-iPhone 4S device is to use a package found in Cydia called Spire. This requires you to have access to a Siri proxy server or an iPhone 4S for the tokens. However, @chpwn (the developer of the package) has stated many times that it will not run on iOS 5.1, because the iPhone 4S IPSW (the actual firmware downloaded from Apple) cannot be unencrypted at this time. This IPSW is needed to harvest the Siri files for use on other devices. He could port it illegally, but he doesn't plan on it. Because the new iPad is running iOS 5.1, Siri cannot be run on it, plus a public JailBreak for the new iPad hasn't been released yet.