Re: Business cases?
I've prepared a number of business cases for a variety of employers and clients. The main skill is the ability to understand/guess the outcome that's required and then to be able to make the business case support it.
There's a good one recently - the A9 dualling cost-benefit analysis showed that the project would return less value than it cost so the Scottish Gov. hired some consultants (not me) to assign a monetary value to the cost of driver frustration. This came to £430 million – £86 million more than the value given to collision reduction - and tipped the project return into the black.