Those cases will help you get in the right frame of mind, but don't forget Accenture case studies are IT focused. I would therefore spend a fair amount of time looking at their capabilities/past case studies on their website to give you an idea of the types of solutions you can offer in interviews.
I presume you're getting the standard Accenture 1 case study interview alone, then a group interview on the same case, then a 2nd 1:1 interview, then a final group exercise? In which case, teamworking is evidently going to be as important as preparing for the case - but is hard to practice! Just remember to be involved and contribute without taking over the group. Its hard to do, but always listen to what others' have to say, and make sure others hear you even if you agree with what's been said. Also, expect some competantcy based questions in the case interviews e.g. When did you work in a team?, but not as much as the first round. They will also ask you how you thought the group exercises went - be honest, but not too honest - a tough question. Lastly get some good questions to ask them!