It looks like Google is working with LG on a Nexus tablet and it may be available this summer or early fall. This report comes from Eldar Murtazin from mobile-review. It seems like a natural fit since Google has already marketed the Nexus One, the Nexus S, and soon to be available, Nexus S 4G. Just like those devices, this tablet will release with a newer version of the Android OS. It is unclear if it will actually be marketed with the Nexus name.
On another note, Murtazin reports that if a hardware partner makes a tablet with Android 2.x, it cannot be upgraded to 3.0+. Assuming this is true, it guarantees that the original Samsung Galaxy Tab will not get Honeycomb.
Note: the above picture is the upcoming LG G-Slate for T-Mobile