Aside from the obvious, I think there are a few that will be black holes for fantasy owners.
The Baltimore situation is a complete grease fire. I don't think they even know who tops their depth chart anymore. You can't even classify this as RBBC. Someone needs to come up with a new razzy term for a 3 RB system.
I think Buffalo is working out to become a possible headache as well. Lynch is clearly the favorite at the top of the depth chart, but 3DB Jackson, and even Rhodes look to steal carries away. Both of these guys have great hands, and are very capable receivers. I doubt they will both play the role of 3DB. There is also the 2 game suspension of Lynch where both of these guys can establish themselves as an important part of the offense.
Believe it or not, I'm also including New Orleans on this list. Yeah I know, this is a super high powered offense, how could either 1 of these guys disappoint? Well, both will get good fantasy numbers for a season total, but the chances of them being hit or miss on a week to week basis is high. Some games New Orleans may throw all over the field, and Reggie will be a solid scorer. Another week they may find themselves 1st and goal with short yardage on multiple occasions and Pierre will punch them both in. I think it will be hard to handicap when to play either 1 of these guys. If they are 1 of your week to week sure starters, you could see some severe inconsistancy.
Another possible RBBC nightmare is Dallas. Barber seems to be the clear favorite, but Felix is not to be underestimated. He showed some real skill last year, and if he can stay healthy, I think he steals a lot of carries from Barber. I also feel that the loss of TO will negatively affect the running game, causing their YPC to take a slight hit.