We're not ones to peer too deeply into the Apple crystal ball, but Geeksugar says that spec-bumped iMacs are due on Tuesday, and the timing seems about right. Nothing major, apparently, just a speed bump and some bigger hard drives, but prices should stay the same. It's still just a rumor, of course, but Geeksugar was right on the money about that MacBook / MacBook Pro bump last time around, apart from saying that multitouch trackpads would hit all of Apple's portables. Perhaps some Best Buy / Future shop employees will let us take a peek in the database and let us know what's up, hmmm?
Update: We've gotten a couple sketchy reports that entries for new iMacs are in fact popping up in retailers' systems, but it's getting hard to focus what with all the grains of salt we've taken.
AppleiMac 27-inch with Retina 5K display (late 2014)