Please try to ID species by description

A miniature iris appeared in my garden a couple of years ago. I don't remember buying it or being given it, and unfortunately I once again missed taking a photo during its brief flowering.

Leaves are at most a foot tall (most shorter), but aren't stiff, so they curve downward and overall height is about 6" or so. Leaves are at most 1/4" wide at widest point.
The flower is mostly lavender and about an inch wide. 3 petals are solid lavender and the 3 falls have a lavender border and what looks like a white feather (delineated by lavender/purple lines) with the "stem" of the feather being pale yellow.

Can anyone identify it or at least narrow it down so I can search more easily?

find some pictures of I. cristata http://wiki.irises.org/bin/view/Spec/SpecCristata

Thanks, crowrita. It does seem to be related to cristata, but the leaves are much thinner and I think longer, and I couldn't find a type of cristata with the feather pattern. I should also say that the flowers were relatively flat, i.e. all petals on the same plane, curving down only slightly at the outer edge.