This was the last AM3 ITX board that was enthusiast grade.
http://uk.asus.com/Motherboards/AMD_AM3/M4A88TI_Deluxe/
Bulldozer's power draw (4 module / 8 core) was insane (when overclocked), the amount of ITX rma's after people blowing boards would have been nuts.
The amount of engineering required to make an ITX board capable of supporting a chip like that is pretty much unfeasable with the amount you'd actually sell.
Another, perhaps the most pertinent reason why board makers haven't supported Bulldozer and Vishera on ITX is quite simply the lack of an IGP.
It might sound silly to an enthusiast, but these days with all cpu's moving to IGP's, trying to sell an ITX board that requires an additional gfx card purchase seriously limits your potential market. (to the point of being unsellable in a volume that you can recoup the r&d costs and start to make profit)
Enthusiasts make up less than 1% of the total pc market.
AMD will no doubt integrate an IGP into all their offerings at some point.
Until then don't expect to see any ITX boards for their flagship CPU's.
The distinct lack of 900 series m-ATX boards is also due to poor market potential.