I am using a Flaming Gravy Fairy. It also had a Li'l Businessman Kit equipped, which has +5% items itself, in case that makes a difference. Softcore, normal, Disco Bandit run.
Edit:
This was the modtrace I did:
mark v steam-hat | | | +10.00 | = 10.0 | | |
plexiglass pants | | | +20.00 | = 30.0 | | |
li'l businessman kit | | | +5.00 | = 35.0 | | |
fat leon's phat loot lyric | | | +20.00 | = 55.0 | | |
Fairy | | | +67.62 | = 122.62019202317981 | | |