What kind of vehicle? I don't see anything in your signature or an intro page.
How much oil is "quite a bit"? Is it pooled and dripping out, or was it a film? Was it the coolside intake or coolside outlet pipe where you noticed the oil? EDIT: Probably the outlet, since you said you removed it to access bank 1 plugs. Any sign of oil on the cool side inlet or is it all outlet side?
Are your BOV's still plumbed into the intake piping? I've seen pictures of the front BOV dripping oil, not sure if this is common on the rear. They can tend to recirculate oil that is already in the intake.
Are you using an oiled air filter (like K&N)?
SHOdded is probably right, I just like to over-analyze things.