Consolidating multiple websites into one: any case studies and UX/IA issues to be aware of? [on hold]

Been given the task to look into consolidation three local news websites into one site, and potentially three specialist magazine websites into one.

This is not something I've done before, so would like a few pointers if I may:

• is there anything specific I should bear in mind when determining the site or navigational structure to make the transition easier for our users?
• does anyone know of any examples where this has been done elsewhere? What was the result (I know MusicRadar 'melded' Computer Music, Future Music, Guitarist and Total Guitar)
• what kinds of frustrations are users likely to experience when visiting our new consolidated site? What can we do to make it easier and more positive for them?

Any thoughts would be most welcome!