More research shows this:
with the following quote:
Something else that deserves your attention is this picture, showing Dan Connors, Kevin Bruner and Troy Molander standing behind "a computer displaying a character from one of their video games". I might be wrong, in which case I’ll edit this bit out later and most of you will never know, but the caveman character might have something to do with their new licence.
Of course, it’s also possible – and perhaps more likely – that said figure is actually part of the "fun smaller games" that Telltale have also promised on their web site. So don’t rule out Monkey Island 5 just yet.
Now, that character doesn't look familiar at all, and I find it hard to believe that Lucasarts, despite their current dislike of the adventure genre, would let that license go, but I thought I'd toss it in.
That said, in a poll on the site, most seem to think it will be Monkey Island or another Lucasarts franchise. The only specific non-Lucas related listing: Boneville.
And in final research tonight, on the Telltale Games website, they do list http://www.Boneville.com
in their links, and Jeff Smith's site has news about this development team. We very well may be on to something.