Okay, update on the Den. aberrans, US ebay seller
Larry's Orchids has it for $14.95 + $8.50 shipping. I don't know much about this seller, but from the description the plants sound BS or NBS and the price is within guidelines... In EU it's available from Popow for 12 euro.
Bulbophyllum ambrosia is available in the US from
Carolina Orchids for $20. I have a lot of plants from them and the quality has always been good so far. Carolina also has Den. tetragonum listed for $20 and they say theirs is a miniature type.
I also looked at Carolina for the Dendrochilum wenzelii suggested by Ramon. Unfortunately theirs sells for $25, but they have a lot of other Dendro. species for $20 and under. If selected, could this one be an open 'Dendrochilum species' project to open up the availabilities a little? Might turn out pretty interesting, I have yet to see an ugly Dendrochilum!
For Cattleya (Sophronitis) cernua, Orchideen Lucke has it for 19,90 euro. It's available in the US from Carolina for $15, from
Jewell Orchids for $18, and from
Botanica Ltd for $20. I'll keep looking to see if I can find a cheaper EU source. I hope this helps!
--Nat