File this one under industry-changing mergers that never were -- Bloomberg is reporting that Seagate rejected a takeover bid from rival Western Digital in October, which would have created a hard drive company to dwarf all others. According to "two people with knowledge of the matter," Western Digital was willing to offer as much as ten to fifty percent more than a competing takeover proposal from TPG Capital, which had already put more than $7.5 billion on the table for Seagate. As you might expect, however, the sheer size of the merger was apparently largely responsible for its refusal. Not only would it have created a huge amount of product overlap and likely led to numerous management departures, but it would have almost certainly faced some pretty significant antitrust obstacles. Of course, neither company is actually commenting on the matter itself and, for the time being at least, it looks like Seagate is content with going it alone.