Unless you change the front pinion angle, i.e. cut the Cs off and reweld them, you need a constant velocity type joint at one end of the drive shaft. The drive shaft at the pinion end is (in theory) a zero operating angle, i.e. straight. The transfer case end has a few degrees of angle.
A single u-joint, when operating at an angle introduces a sine wave based oscillation in the rotation that increases as the operating angle increases, aka vibrations. One way or the other, you want to have this cancelled out through the entire driveshaft. The c/v joint does it internally to the joint with 2 phased u-joints, the vibrations cancel each other out right there. The standard rear drive shaft does it with 2 phased u-joints at opposite ends. Think of that a a long c/v joint, using the tube instead of an H girdle.
So, the short answer is you could, but you'd have major vibration problems.
