You might investigate using a liquid ring vacuum pump with the oil as the liquid.

Do you even need a pump?  With that amount of air flow you could probably blow the oil back to the tank.  This type of scavenging is done on some turbine engine bearing sumps.  It may be viable if you don't require a vacuum in the sump.

Yes, the oil ring or a multi stage centrifugal vacuum pump.

Could you use a venturi? You've got airflow/pressure, but is it enough for an eductor to work?

Thanks for the suggestions.  Our air is starting at atmospheric pressure (leakage into the bearings), so we don't have any air motive force to work with.  We are using a "dry rotary claw" vacuum pump to handle the air leakage, and a Wilden-type pump to handle the oil.  We're running the air-oil stream through a vertical separator vessel and taking oil out the bottom, air out the top.  We have a demister on the vacuum pump discharge.  We'll start up this week, and I'll let you know how it works.