Try mounting a Phal that's known to be fairly easy to grow first. A species to try out would be Phal schilleriana. Another would be Phal philippinensis. Yet another may be Phal stuartiana. Another possibility would be Phal equestris.
The species of Phals that need copious amounts of moisture through rain and humidity are usually much more difficult to grow mounted.
Doritis pulcherrhima are lithophytes in the wild, so mounted culture should work well for these too.
ImageShack® - Online Photo and Video Hosting