I'm sure I've read here that the 3rd tuner will be activated in Q1 2011, the TiVo software only supported two tuners for the US so I assume they're having to write the code to add a third.
I highly doubt (but could be wrong) that it'll have HDMI 1.4, there are very few devices that support it and it means all new cables as the spec has changed slightly to incorporate higher bandwidth and new features.
Apps is something I'm interested in, can't find any information about who decides which apps get on the platform, if they'll keep this "walled garden" approach or if they'll open it up. Remember that Virgin Media essentially only lease the Virgin brand from Branson and they've got nothing to do with the rest of the group. I don't think a specific Virgin Trains app will be there at release.
Have you got a phone with Internet access? Why not check out the National Rail Enquiries mobile site?
http://pda.ojp.nationalrail.co.uk/