As spotted by NeoGAF user ekim, rumour has it that Bethesda shared some information on Fallout 4 at E3, behind closed doors to an audience sworn to secrecy. One member of that audience was apparently willing to take a risk, however, and has provided the following info, which – it goes without saying – may all be completely rubbish but is reprinted below (typos and all) for your interest:
> Fallout 4 has been in development since January 2011 by a small team, as the majority were working on Skyrim.
> As of February 2013, the team working on Fallout 4 is the size of the team which was working on Skyrim. This is due to Skyrim development ending.
> As it stands now, Fallout 4 will release on Xbox One, PS4, PC, Xbox 360 and PS3. However, this is still subject to change.
> The actual announcement for Fallout 4 will come BEFORE E3 2014, but will NOT launch in 2014.
> The expected launch is in October 2015.
> The game is (as of June 2013) 55% complete, consequently, voice actors will be hired towards the end of 2014.
> There is no planned multi-player, but there is a possibility of Co-Op locally.
> The game will take place in Somerville, Cambridge, Arlington (and surrounding areas). The main setting is in a Post-Apocalyptic Boston. However, this area will not be immediately accessible.
> The story is not clear, however, Vaults exist.
> The 37 second trailor starts starts with a half-broken phone sparking. The scene pulls out slowly with the stereotypical music you would hear. Slowly you work out the scene is pulling out of a belltower. As it pulls further out, you see a destroyed town around. This is Boston. Suddenly, you hear the bell chime loudly, and the screen changes black instantly. The words of Ron Pearlman are heard "War... War never changes...". The logo for Fallout 4 appears with the 5 platforms above listed.
It's hardly surprising that Bethesda would move the Skyrim team – or at least a team of equivalent size – onto Fallout 4 once development ended. However, if the studio follows its pattern with the Elder Scrolls games then we can expect The Elder Scrolls VI to launch in around 2016, supposedly a year after the expected launch for Fallout 4. However, The Elder Scrolls Online may delay the next game in the series, freeing up the team for Fallout 4.