I make my levels as Huge MDL´s. With completly reprogrammt scripts, that work quite fine. I Build the levels completly in 3D Studio Max an export them to Game studio. I need only one big texture for the whole level ( except of Models i put in afterwards, like Trees or such things). I Texture the whole level in Bodypaint and so you can buile huge out- and indoor levels in quite a short time, and they look very good. The only negative thing is, that u must change a lot of scripting to make a mdl level work the same way like a block level and the 3ds max an bodypaint are very expensive.