Nathan - If you have access to an MRI, it might be interesting to see if there is any evident difference in traditional vs SV vs steamed. Sort of like the work Heston did with yogurt marinades. Exactly what fat are you using to coat the duck after steaming? I only ask because I wonder what effect the long low cooking has on the fat. I may try the experiment of simply holding some rendered duck fat at 70c for 8h and then doing a blind taste test vs duck fat that has been recently rendered and taken to 70c for only a brief period. My guess would be that I would not be able to detect any difference, but its not something I would want to discount. Also, last time I made confit, there were other guests at the party (spices, ect.), and I'd have to think they would benefit from some extended contact with warm oil as well. This would seem more influential than the means of heat transfer.
