PART SOLUTION 1:
I couldn't find how to do this in the end, but!
Best idea is to export the waveform as a png using the highest print setting, on my system this gave me a 3200 by 4300 image, easily ported to .eps etc.
PART SOLUTION 2:
The other solution would be to export your database to cvs, open using MATLAB, create a function that is able to threshold each of the waveforms you are interested in, creating a time array of zeros and ones for each voltage waveform in the bus. This can them be combined with other similarly thresholded waveforms to create a Bitdepth*TimeSeries array. This could then be converted to Decimal*TimeSeries array using the bin2dec function.
For my thesis the MATLAB analysis method was too lengthy for just a few diagrams, if however you need to run statistical analysis or analysis of long strings of simulated output data I'd recommend this approach.
Ed