the texture actually repeats outside the 0-1 space so having UV's outside it although it is possible is not general practice . To take any size UV snap shot you want (Maya doesnt like textures over 4K much) , select UVsnapshot under the polygon menu in the UV texture editor and you can choose the resolution in the window that pops up.You can also set the range here too (0-1 or entire space or user specified).