I seem to have missed this one. Defiance Machine (http://defiancemachine.com) has a controlled round feed action out to compliment their existing actions. See photos here, I'm too lazy to get images to post:

http://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/9556337/1

The current lead time is 10 months and they only have standard and magnum bolt heads (long and short actions). I would love to get one of these in a Rigby bolt head to build into a 300 Norma.