Roadmaps seen by the INQ show that on the 23rd of July Intel will relegate the family known as 6X1 to entry level, with the 661 slashed from $400 to $183 and the 651 from $273 to $163.
The 641 and the 631 will all but disappear, because they will be priced at $163 too. Other members of the 6XX family such as the 670, the 660, the 650, the 640, and the 630 will just slide off the chute like a burial at sea, weighted so they'll never re-surface.
A similar thing is happening to the 5XX family - on the 23rd of July he only surviving members of this 1MB cache family will be the 541, the 531 and the 524, priced at $85, $75 and $69 respectively. The others will just vanish, possibly roaming the planet as ghosts looking to re-incarnate as embedded chips.