Good idea, Neil, and one I struggled with before my recent trip abroad. I don't think there is such a database.
There are three possible methods that I used:
a) Join a newsgroup for Orchids of the Country you are about to visit. Often people in other countries (where the orchids are more plentiful and less at risk) are more forthcoming with sites than here. These will be found, if they exist, via the method below, or a search of Yahoo, MSN, etc.
b) Do the usual Web search for the orchids of the country to see if there is a local Orchid society or expert, and Email them.
c) Join the Hardy Orchid Society (make it quick, their year runs from 1st May); they are dedicated to the study (and propagation, incidentally) of Wild Orchids in Europe. There are a lot of members who have a lot of experience abroad - worldwide, not just Europe. They can be a little cautious, but go to one of their meetings and meet the people to gain their trust, and you will never look back. They have a website with an online membership form, and it's cheap.
Because I had the same problem as you recently, I had planned to find or start a resource - I am starting here by posting my Italian stuff (once I've identified all the tricky ones!!). But watch this space and keep in touch.
By the way, hope you had a good trip.