Client wants the same site in a different industry

Whats the thinking on triggers for duplicate websites?

[exformation]

My client has a successful website representing other companies in a certain industry. He's keen to repeat the effect in another industry. Needless to say I'm keen to help him.

The question I'm facing is how much will the new site have to differ from the old one? It will have seperate incoming/outbound links, but will I have to change the url's or will industry1keyword.com/widgetservice and industry2keyword.com/widgetservice happily co-exist without one site being punished?

The key for me is that search phrases I'm optimising are industry1 widgetservice and industry2 widget service, which causes my dilemma.

Also are there any thoughts on repeat content? Although this is not a major issue as there is not a huge amount of content, as site is more directory based, and thankfully, being fairly specialised hasn't needed a huge amount of content to do well.

Any and all thoughts most appreiated!