Personally, I think mixing species is far worse than housing two of the same together (which I also think is a bad idea). They have different habitat requirements (although there are similarities), so you'd need a viv that's long (for the corn) that has a fair amount of height (for the green, because they tend to be more arboreal than something like a corn). From a monetary perspective, it'd be cheaper to buy two vivs - one meeting the needs of the corn, one meeting the needs of the green.
If you housed them together, what would you do about feeding? They have entirely different diets. Greens eat wax worms, crickets, etc. And if you do a search on feeding corns crickets, you'll get the idea that maybe it's not the best (or acceptable) diet plan for a corn.
There are plenty of other reasons why you shouldn't do this, but like someone already mentioned, do a search on housing corns together, then add in the factor of the second "corn" being a completely different an unrelated species.