If you're patiently waiting for an update for your LG G-Slate, we've got good news. According to a moderator at the official LG community forums, the Honeycomb 3.1 update for the G-Slate should start pushing out as early as Aug 8. Carrier versions should follow soon thereafter, with Docomo in Japan already having scheduled their update to start Aug 10. Of course things can change, and we're only sure once it actually happens. We have no word when T-mobile is to begin sending out any update for their version, but have reached out to them asking for any information they can share. We'll let you know what, if anything, they have to say.
Source: LG Forums. Thanks, Caleb!