Thanks for all the help!

As it turns out, it appears to be my flat-plate heat-exchanger leaking veggie oil. After washing out the engine and underbody, I drove it for a bit and brought it home. Sure enough, dripping oil from the same spot (that metal bar in the first photo I posted, from one of the holes in the bottom of it. I stuck my gloved hand underneath it and was surprised when it looked like, and smelled like grease.

Now it's a matter of finding the time to pull it out and find out if a hose split, or if the thread-sealant is leaking....it certainly is losing a significant amount of grease, and this is without even switching over to veggie oil. I'll post back when I know more.