Paphiopedilum sanderianum
I am thrilled to find this plant flowering with long petals, 24 inches (2 feet) and petal may still be growing. Although after I took these photos, I was moving this plant to another location where I am least likely to disturb it. In the process of moving this plant, I broke one of petals.
Besides Paphiopedilum rothschildianum, Paphiopedilum sanderianum is one of my favorite species because of its long petals.
Longest petal length per award record is 'Raven Cliff Falls' AM/AOS awarded in 2004 95 cm - about 3 feet.
Adding photo of another Paphiopedilum sanderianum which bloomed earlier.
These are all seedlings from Carter and Holmes purchased years ago as small plants