A
Ayreon
Guest
niveum x appletonianum?
Kevin, Ernie, Roy, and Robert are all on the right track. This might give it away, but a noted orchid expert when speaking about this species stated: "Hybrids made from this species have realatively little worth other than their novelty value."
Paph fowlei.
David
Good guess, David.. Ross, is this plant any smaller/more compact than other similar (brachy x barbata) hybrids? Cos fowliei is a rather small plant..
I believe its niveum by something barbatum. There are some dainty species I'd rule out because noone with a healthy mind would breed with them and some others because they distribute colour in a different way (tonsum, mastersianum).
How about Judy Erdmann (x urbanianum)? If I had a second guess I'd go for wardii.