I still haven't played Arma2 but I downloaded the free version just to try this out: Take On Forum
Its an Addon island for Arma that can be inserted, with a few errors, into Take On. The best instructions are on page 7 or 8. You will also need to add the plants files to get the full effect. It's a strain on my mid-level rig but it is absolutely gorgeous! One caveat: The creator of "Chenarus" hasn't specifically given permission for the use of his island outside of Arma. He sort of grudgingly does so in the discussion linked above.
After seeing this, it is hard to not be convinced that these two products, Arma and the ToH flight models will eventually merge.