Ok, here is the theory for geting bigger levels with the same if not better framerate. I kinda borrowed this idea from RealityFactoryPro. This has not been tested yet, but I will report results and have a small download or pics if sucessfull. I will also report if it is a total failure.

Therory
: At the start of the game set an animation that changes the height of the player to make them closer to the ground. Experiment with wall sizes to see what looks good. this will give the illusion that the world is bigger. Be sure to scale your jump height accordingly unless you want Supermario jumping. Md2s must also be checked and decreased in scale.
The Downside
: the smallest spaceing you can work with is 1cm so if your size goes from 300 to 150, what would have looked like 1cm away is now looking like 2cm away. As we have no control over player width, door sizes have to be checked. So scaleing down door widths and passage ways have to be checked carefully so you dont get hung up on doors.