I was hoping not
I received word from a few folks that the EF 100 f/2.8 Macro has been discontinued. The lens currently still appears in Canon Canada's price lists as well as Canon USA's. The manufacturing of the lens may have stopped.
I hope this lens isn't gone, there's a big difference between $650CAD and $1300CAD for a 100mm Macro. I own the aformentioned lens, and I have no plans to upgrade.
I'll look for something definitive.