This really caught my eye because the shape and especially the colors are somewhat similar to my Miltassia 'Royal Robe". I can tell it's not that, but it looks to me as if it has a good bit of Brassia in it, and the leaves, from what I can tell, resemble Miltonia leaves. What, if any, do the pseudobulbs look like? And about what size are the blooms? I would never say I could id it, but I'd be very surprised if it wasn't a hybrid from the Oncidium Alliance. No doubt there are other who have far more information and experience than I do. It's very beautiful and I hope you do get an id!
Maura