I've got an underfolder and am a leftie and am having a hard time figuring out how to attach a sling that would work for me as the sling swivels are on the wrong side and I can't come up with a solution to bypass them.

I've got the Blueforce gear wire loops, which are great.  I can get an attachment point on the front, around the barrel that way.  However, I can't find a way to get a rear attachment.  I tried putting a loop on the back of the wire stock, but the sling will pull rear hinge of the stock up like I'm going to fold it.

Before you expend a lot of time trying to attach the sling to the right side, lash up a temporary attachment and carry the rifle around. You may find that having the operating handle in your back is a sufficiently unpleasant experience to abandon the project.
Should you find that to be true, you can always sling the rifle from the left shoulder muzzle down.