This Rogue Trader-era Eldar Howling Banshee Exarch was a 1990 Jes Goodwin sculpt. It was the same sculpt used through 2nd. Ed. Warhammer 40K. It was part number 071572/3 in the 1991 Blue catalogue.
It can be seen painted in the 2nd. Edition Warhammer 40K Rulebook:
