Use uv Tiles on your model and unload regions you dont need in ram.
Right now, I have a character with 14 2k uv tiles and its just a bust, and all the maps fit into memory. Sometimes you get that warning, and you can still squeeze quite a bit into ram :) I dont know why that is.
Anyways, try to be effecient with your maps. Use 2k maps and uv tiles instead of large 8k maps.
Btw, .mud files are large, it doesnt have anything to do with vram.