I need to design an LO buffer that drives a double balanced mixer, but i'm not sure what the structure of the oscillator will look like.  I understand that the LO will be fixed at a specific frequency, so is it ok to use a VCO type structure to create the oscillator?  Or can i just use a pulse generator to produce the LO signal?  Would anyone be able to point me to references that might inspire me?

Only the buffer needs to be designed.  The LO buffer needs to drive the mixer with a differential signal and the assumption will be that the input to the buffer will be driven by differential signals from the VCO.  The LO signal will be 300mVpp (1.8V supply).