Yes, it's definitely Paph. Ho Chi Minh and a good one. Often the pouches of this hybrid (and also vietnamense itself) are not solidly coloured: yours is and the form is almost perfect so you've rescued what turns out to be a lucky plant. Congrats!Update: the mystery seems solved! Though you guys had already solved it, of course. But I feel comfortable tagging this plant as Ho Chi Minh. Also, it’s a darn fine flower if I do say so!