Multimaps are no problem, if you notice though the map sizes are powers of 8. Valid maps will be a power of 8 (16*16, 16*32 etc.) if they aren't the proper size then they are adjusted by the engine. Multiple maps are actually a great deal easier to use than a single map. Single map texturing is really giving me a headache but it's good practise. The Morrigan fighter (previously Excalibur) is almost done (LOD0 anyway) and it uses a single 256*256 map, I'm experimenting with the Mars though, if it looks right I'm going to be using 3 512*512 maps, here's hoping it works well ingame.