They're listed for $65k, but you can probably get them down in price....I would low ball offer $45k, see what they come back with! I've bought stuff from Solaris and almost always been able to get the prices down.
How many jobs has he had to turn down because he didn't have a 120K rig? What does a 120K rig rent for in your area? What markets does the company currently serve? For my money I would stick the 60K into some nice LED lights Mac Auras or Quantums. I feel those are more versatile fixtures and might get a better ROI than a 120K rig.