We did have that one week where Apple did do a PR for a new product (almost?) every day, so there is technically precedent...
Yeah. If you want to you can say Monday is "a month after" WWDC with that lasting till Friday. You could also argue that three new products introduced right before the earnings/investors call would be nothing to shabby since there has been nothing new to sell for three month now. Especially with the 27 inch being pretty much of the shelf for two month by now it would be decent to just have the new one in stores before people ask questions on the call.
Then again. If it's not there (we only got a 100% unproven twitter account after all, might just be boredom on the weekend) they would just say "we have great new iMacs in the Pipeline" like they did at WWDC.
But like i said the other day. Apple dos not care about you, they care about their stock holders... so maybe... i just don't want to get my hopes up again and wast my concentration on refreshing the Apple Store in the afternoon...