So the SDS-470 is still available:

Delivers 300 watts @ 8 and 600 @ 4. Given the current naming convention, Tom should have called the complete amp the SDS-600.

Class D Audio SDS-470C Custom Class D Amplifier - Complete Amplifiers

Sadly, the price has gone up $100 from $590 (when it debuted in the old case) to $695 in the new case (Tom did note when it appeared that the price was going to go up - so part of that difference is due to introductory pricing and the remainder due to the new case).

Still $700 for the SDS-470 is still a very good price for a complete amplifier with those specs. One of the first user reviews for the 470 in the case is out:

Class D Audio SDS-470 full review