That is odd! I have been trying to figure out what it could be a natural hybrid/hybrids with. There is very little about it that is characteristic of callosum. The dorsal shape and colouring is off, the petal attitude approximates, but the petals themselves are off, the pouch is off, and the overall floral shape is off. This is even more different from callosum than potentianum is.
Where is it from?
I think it is a interesting and subtly attractive Paph callosum. While it isn't a typical callosum, or typical var. sublaeve, there's really nothing else it can be - something along the callosum/barbatum clade. There's really nothing else that could contribute these characteristics to a hybrid, is there?
Is it wild collected? Is it typical of the population it came from? Is this flower even typical for this plant? If this is a first bloom on a small plant later flowers could be much different.
If it isn't collected, what did the parents look like?
Published varieties are often based on one or a few plants from a small area, not reflective of the broad variation even in a single population. It isn't realistic to expect every plant to correspond exactly to a published description, or match the pictures or plants you have seen before. Every seedling is unique. Every population is still evolving.
This plant came in as paph. callosum var. sublaeve from northern Malaysia peninsular. They are the smallest plant amoung all the paph callosum. This plant is the odd one out, as the others within the group are of typical var. sublaeve, warts on the upper part of the petals.
I have a couple of plants that look like these that were labelled Paph. thailandense. I will wait to cross them until next year but they really look very similar. Very little in the way of warts - I think one has perhaps one small wart. They are very pale and really quite unique. I bought a couple of the pictured plants from Tropical Exotique in Redland and will cross them and also perhaps do an outcross to one of mine.
I'm going to try to post an image of those "Paph thailandense" plants.
Well Ive been trying to upload via the 'manage attachments' and I haven't yet been successful. Guess I have to find my old Photobucket account. I hate this process.