During the GDC in San Francisco last week, senior designer of Harmonix Dan Teasdale held a keynote panel. During the session, a PDF slide show was shown to the audience. However, at least one of the slides was not presented to the crowed. Kotaku uncovered the missing picture and it had something very interesting, that might have confirmed a possible game in the works.

If you check out the picture above, this was the graphic that was supposed to be shown off, but decided by the company to be scrapped. If you study it, you can obviously tell the point of the slide is to show what ‘guitar/instruments’ music games have come out and will come out in the future. Pretty much every title has been announced; however, some of them have only been rumored. The most notable game yet to be revealed on the list is the Lego Rock Band. The Lego version of RB has been talked about for sometime, but has not been unveiled. According to many sources, Traveller’s Tales has been rumored to be developing it, but everything thus far is only speculation. Although now, it looks like a pretty safe bet Lego Rock Band will indeed be released. When? Well that remains to be seen. But if we go by the graphic — we should see it before or around the same time the Beatles Rock Band game is in stores, which is on 9/9/09.

We should also note that if you look at the same picture, you will see the letters “GH:VH.” I think that is a pretty strong indication that would translate to the rumored ‘Guitar Hero: Van Halen.” Although, how Dan Teasdale knows about the Activision published title is a tad strange.