Source from Singapore forum clubsnap, a Canon guy told us that the EF 200-400mm f/4L IS USM Extender 1.4x wouldn’t start production until Q2 of 2013.
And the price is told at $16,000 (Singapore dollars), convert to $13,000 USD. A bit high than the price we heard before as $11,000.
The official announcement for this lenses is said coming soon.