4.7 was delayed so the buildservers could get 5.2 ready. 4.7 is probably in the queue now, but it takes a while because CentOS doesn't have a million dollar hardware budget, and has to schedule things to best use the hardware available.
What changes will be in CentOS 4.7 vs. 4.6? I would really like to see NCQ support on SATA drives. Then again some have said it does not help much. I have an email server that is somewhat disk I/O bound.
Matt