I tried Aquamart and Stone Aquatics. Stone Aquatics didn't know what a bulkhead was, lol. I have some thread x thread laying around that might work, but I think that the space is too tight after putting on a female adapter.
If you have them, that would be great - Aquatic Art and Neptunes are just so far for me during the work week. If it turns out you do have one, please let me know. I work out that way...