I bought a really nice commercial Mauser and I'm trying to figure out who made it. It looks like an FN, but has German eagle proof marks. Any idea who made the action?

The "Eagle N" is a commercial German proof mark. So it would be German manufacture, and therefore not a FN. But there don't seem to be any other manufacturer's markings, at least in the photos you've posted.

Likely a postwar commercial hunting rifle.

So my theory so far: FN action, purchased as a bare action by a German smith, which was then assembled and proofed in Germany. Now that I look closer, the ML on the bottom is identical to my FNs.