Taking Alan's advice, I did contact Customer Service and was told "With regards to your query, we would like to inform you that Seagate neither repairs drives nor does it undertake repairs of separate components/accessories. Please also note that in-warranty drives are exchanged and not repaired."
I realize that three customers doesn't exactly constitute a groundswell, but at the same time, it's no longer just an isolated incident. When you sell millions of units, you are always going to have a few parts fail. Why would you not offer to SELL replacements for those parts? Can you imagine Ford refusing to sell side mirrors and insisting that they have to exchange the entire vehicle (or nothing)?
Regardless. All I really want is to know is where I can get a replacement module, p/n 100453518. Doesn't even have to be new. Refurbished would be fine. Maybe off one of those exchanged drives...
PS I do give a hoot. That's why I bought a Seagate drive to back up my data on.