My recollection from a LKE I had several years ago, where the "only real property counts" rule wasn't in effect, but the "real property isn't like to personal property" rule was the problem, the attorney-CPA 1031 specialist the client used opined that if the immovable personal property was less than 15% of the total, the entire thing could be treated as real property. My client was exchanging mineral interests (some of which came along with the equipment portion of the well) for mineral interests (either undeveloped or no royalties, so no equipment).

I don't have a cite for you, though.