A permutation on permutations

[Arthur Siegel]

Was able to find nice stuff on the python-list archives 
as to list permutations, list reversal, and removing 
duplicates from lists.

My problem is to combine them.

I am feeding control points to a curve function, and
want all permutations that result in unique curves.  
For this purpose a sequence is duplicative 
of its reverse, i.e. [1,2,3,4] == [4,3,2,1], etc.

So am a looking for a function to return all
permutations, excluding duplicates as defined above.

Ideas appreciated.

Art