This is actually one thing that Java 1.5 has that I'd like to see in Python - the LinkedHashSet and LinkedHashMap. Very useful data structures.
For those who don't know, these implement a hash set/map which iterates in the order that the keys were first added to the set/map.
Such a data structure is fairly simple to implement, and removing duplicates then becomes:
unique = list(linkedset(orig))
and you're guaranteed to maintain order.
Implementing these is fairly simple.
Sounds like a good candidate for the collections module. Of course someone will need to implement it. ;)
STeVe -- http://mail.python.org/mailman/listinfo/python-list