I would imagine they've got stuff in the pipelines, but they'd most likely want to get through the iPad intro season before distracting the world with lesser updates.
It seems like Apple is very careful to let their current inventories run nearly dry before introducing updates. I'm sure it saves them a lot of money but they should probably be a bit more concerned with keeping up with the market.
When your business model revolves around making the previous product look old and unappealing, you work hard to make sure you have none of that model left when the new one launches.