Alternative to emitter-follower for simple BJT voltage regulator
Check the datasheet of an LDO regulator. Things won't get as simple as one or two transistors though. The stadard trick is to do the comparing at a lower voltage (using a long tailed pair), and to drive a PNP series transistor.

This design can be found at http://www.discovercircuits.com/Andy/Discrete_LDO_Voltage_Regulator.htm :