I have just had a very nice reply from David at rePotme.com in response to my inquiry about clear plastic Paph pots.
He said that he will investigate to see if anything is available, and he also mentioned that he is meeting with his pot manufacturer this week, and will explore the idea with them.
I'll let you know if anything comes of it!
PS. They have some nice tall ceramic pots - probably for cymbidiums - but with the holes in the side to allow air in, they look like they would work for anything that has a deeper root system.