The timing seems in-line with reports that Apple will be announcing the iPad 2 before the end of the month. It also seems to point to something else: the iPad 2 will have some sort of different form factor. Or, at least, it would point to that if accessories such as cases are part of the clearance. We certainly don't expect to see any change to Apple's dock connector.
While the announcement of the iPad 2 is expected soon, that doesn't mean we'll necessarily see the iPad 2 immediately. Typically we would have to see some number of weeks elapse before the new iPad launches to retail.
It's still unclear what exactly will change with the iPad 2, but it's expected to at least have a front-facing camera. We also expect a dual-core processor and other improvements, but nothing radical, but certainly something more than the iPhone 3G to 3GS refresh, where little changed except for the internals.