[Blom]

Both of my bulkheads were from red coral, other aquarium shops or a hot tub supply store maybe. Not sure. As for attaching a filter head just use pvc fittings. If I'm understanding you right you could just use a length of 1 1/2 pvc pipe to a threaded fitting which you could attach the filter head. And yes bulkheads come with threaded ends as well if you wanted to purchase new ones. What I would recommend is to go through some of the tank build journals on this site to see how others have gone about their builds. Useful tips and tricks, it alleviated many of my issues. the 1 1/2 inch drains are good, have you looked into a herbie style overflow (search this forum). the return lines will depend on your return pump. If you have a pump that has 3/4 inch output I would recommend running that the majority of the distance if not the whole way.