Quad core CPU's are currently not available (those that are are ES versions and will almost certainly differ from the final retail version).
There is no way any company will 100% guarantee you a motherboard compatible with Kentsfield right now.
There is no reason at all why the current 965 based boards will not be compatible with Kentsfield (including the GB DS3, DS4, DQ6) however once again you will not get a straight answer either way.
What makes you think the DS3 won't be?