I’ve used glDrawArrays in combination with glInterleavedArrays() and you are right, it really does eat polygons.

You might be able to squeeze a heap more performance by using Vertex Buffer Objects if you are not already. Essentially, VBO’s allow you to store your Vertex/Normal/Texture/Indexes in video card memory. You can still use glDrawArrays() or glDrawElements() to draw (from the arrays now stored on the card), but you don’t transfer the whole scene over the bus to the card each frame.

I imagine the nature of the data in your level editor is an almost perfect fit for speeding up with VBO’s. The scene would be drawn many times before being updated(the arrays changing). An update would at worst, approach the speed of using glDrawArrays() with client side arrays (The whole scene is updated and sent to the card).