I actually have one of those dell bays, and tomorrow I am going to try to make my own extender using the male JAE 50 port in the bay and the female port from a broken drive. I just need to get a finer head for my soldering iron.
Mine came from the big blue one that had the crt built in. It was a tray loader though, not a slot load, if that makes any difference. I don't know if it would work with newer drives though as I only used it with old server slimline/laptop drives.
Edit: I was confused by the response earlier I guess. I got one of the things shown in the picture that converts the drive to ide with the separate power connectors, not the thing with the cable shown in the dell picture. Maybe it's a different way of doing the same thing, if so ignore this edit, lol.
Sorry if there was any confusion. What I need is a JAE extender, which has the optical drive's slim port on both sides- like what Mach linked to:http://paul.thejennis.com/JAE50/About.html- , not an adapter, which converts the optical drive's port to IDE or SATA. Those are readily available.