IBM’s potential merger with Sun is hardly a done deal, and reporters at The Wall Street Journal and elsewhere now think the deal may be off. (For the record, neither OEM has yet commented on the deal.)

Which, for EMS companies, is probably just as well. Deutsche Bank estimates a merged IBM-Sun would be able to cut as much as $1 billion in costs from the bottom line. Some of that, no doubt, would come from deleting redundant product lines and even greater buying leverage with the companies’ respective suppliers.

Sales to Big Blue make up about 10% of the revenues at Celestica, Benchmark and Sanmina-SCI, five to 10% of Jabil’s revenue, and two to five percent of Flextronics’ sales. Several of those companies supply significant volumes to Sun as well.

Faced with the pullbacks of Nokia and Alcatel-Lucent, which took some $6 billion combined out of the EMS industry’s collective pockets, word that a deal is off should touch off industry rejoicing, even if just for a day.

If anyone has reason to be sad about the reported deal’s collapse, it would be Sun, which was already on shaky ground. Instead of Big Blue, Sun might turn out to be just blue.