Italian site Spazio Games has a huge list (Google translated - original version here), which is now also on a sister site, of games with release dates in 2007, the info apparently freshly gathered off Xbox.com.

These are the items of interest:

80. Fable 2 - by Lionhead Studios - Release given 2007 TBA (Official Situated)
176. Project “Dimitri” - by NGS/Peter Molyneux - Release given 2007/8 TBA (Further Information)
1. B.C. - by MS Games Studios (Further Information)

This should all be cautiously believed at most, but if it is true … oh my god - although of course Lionhead are only supposed to be developing two games, not three.

Stomp 224 noticed the mention of Dimitri. A genius.

On one of the sites, the disclaimer is:

We attend confirmations or refutation from part of Microsoft.