My own companion just got hit with the "equipment spawn". I noticed when the attack notification messages for his spear suddenly indicated that it had decorations on it, which it didn't before.
I had previously equipped him with a full set of bronze armor and an elephant leather backpack using DfFusion. Interestingly, he still has those pieces of equipment; however, they are all decorated and/or higher quality than they are before. They're definitely still the same items, though; his spear and shield still have kills from much earlier recorded on them (despite the fact that the shield is now Exceptional instead of its previous quality level), and they're made from the same materials.
He also has a cap, dress, coat, braies, skirt, left and right gloves, and a pair of socks which he did not have before, all of varying quality and decoration levels. (It should be noted that when giving him equipment using DfFusion I also removed all of his clothing except for a braies, which he is STILL wearing- it's actually starting to wear out, and is the only item not decorated/quality improved).
He is also wearing a metric fuckton of trophy jewelry, made from bone, tooth, nail (!), hair (!), and horn.
EDIT: I went into DfFusion and swapped control to him. He's actually HOLDING quite a few of the trophies in his hands.
Further examination shows that he was wearing or holding somewhere around two hundred and ninety trophies. Good grief. Did I mention that dropping them all increased his speed by about 20 units, indicating that he was wearing or holding so much jewelry that the weight was slowing him down? I'm letting him keep the clothes for now, they're pretty nice and most are very high quality. A full eight items are masterwork, including his bronze helm and one bronze high boot (but not both? seriously what.) All masterwork items are listed as "created by an unknown artisan", like other spawned items on high-level enemies.
Closer counting shows that he had two hundred and eighty-six trophies, which matches his number of listed kills exactly (sum of notable and non-notable). That explains those, at least.