Basically, they may think the wordpress solution is a little too Mickey Mouse, but once they hear the difference in price, they may decide they want to pilot the idea like this and if it starts to fly they can develop their own custom solution.
I have to see what these plugin and theme guys want to tweak stuff, but most will work out of the box, I think, so it shouldn't take much. Usually the biggest job is hand holding.
I'm thinking if one size really fits all, and it's as easy I think it is, I bet we are talking $2500-3500(?) retail, and if it's a hard one and it's a pita, $5k-7k(?), and if you wanted that functionality from scratch, $20k++(?)