Spring RTS Engine

Unfortunately, I have neither the skills for it nor the time to learn them atm... My question was more out of curiosity : in all the discussed solutions, I didn't see this once, so I guessed that there is a reason against it. So I'd be curious to know why. After all, it does seem to be the simplest ...

Sorry to necro like that, but this was the most recent thread about the map edges I found.

What is preventing the Spring engine to use a bigger heightmap (or several ones?) than the (playable) map, to generate a mesh beyond the borders?