This just in from Tim Bowness. (For those who don't know, Bowness is Steven Wilson's musical partner in No-Man, as well as having an extensive career of his own.)
"...Of the sessions (some of which I’m not allowed to mention yet), one is an unexpected Country cover with a well-known guitarist, one is a 17 minute all-star ‘tribute’ (wherein I massacre a Prog classic!), one is a ballad for a Musical, and four – including three with Peter Hammill – are for a Saro Cosentino album (featuring Gavin Harrison, John Giblin, David Rhodes and others). I’ve also recorded a favourite Peter Gabriel piece with Peter Chilvers for an upcoming PG tribute release."