This was one that I though looked close, but Supreme Sultan looks more ruffled and maybe more burgundy in the falls. It does feel like that sort of vintage. As far as the height Lucy mentioned, I can't rely on that much as sometimes I get shorter heights, especially on newly planted things. This thing has not been healthy in the past, because it never bloomed where it was previously located.
It is a good candidate though, because I remember seeing it being offered at sites I bought from often in past years like Schreiners - I think it was popular.
Another problem with the NOID game is that the same iris can vary in color. I now have Smoke and Thunder Growing in 2 places, one expected, another unexpected. They look slightly different in the two locations. Same for Haunted Heart, expected and unexpected. The beds have different sun and different soil.
IrisLilli said: Not sure, the only one I have that looks like yours is
It is an older cultivar introduced by Schreiner in 1988.