That's actually a good idea. And definitely an ambitious one!
Porting Saharani is very difficult, but somewhat possible, but, Chernarus is impossible. To my knowledge it is at least 5 times larger than Nogova, making it, well, impossible for OFP engine to handle, even with modern quad-core CPU's. I'm not even sure you can create islands that large!
I personally would not suggest porting ArmA1 campaign, it was not the best of the campaigns (no lovable/hatable characters, no characters at all, infact, no real story, etc.). But I am not sure about ArmA2 one, since I never played it. From ArmA1 only user-made campaigns are really worth porting (in my opinion, at least), campaigns like "The Cause" by Rejenorst (an excellent OPFOR campaign), of course if the author gives permission first.
I will track the progress of this ambitious idea, but I myself would not be of too much use, at least when it comes to island porting.
Good luck with the project,