With all this talk about HP and Palm's upcoming tablets, perhaps it's just a coincidence that the company has officially filed for a new trademark that, for all intents and purposes, screams out "tablet." At the moment, it's impossible to say whether or not HP plans on using their recently filed for Touchpad name for anything at all, let alone a tablet. But, tablets are mentioned in the filing, if that's any sizable indicator.
The trademark covers plenty of devices, making sure not to name one specifically. It actually covers not only products, but also services. However, "tablet computers" is the one many are most interested in. With HP's webOS announcement right around the corner, it's likely that the tablet devices we've seen hit the Internet will be officially named and detailed. Whether or not Topaz and Opal, which are currently the codenames for the tablet devices, stick around remains to be seen.
It's also possible that the Touchpad name falls under a product lineup, featuring tablets and other devices of that sort, and not one particular tablet (or other device) specifically. We'll have to wait and see if the HP Touchpad name pops up anywhere else.