my source for the rumour is the same gentleman that released that notorious pdf paper about EP1, which was later to become E3.
In an interview (pretty interesting in itself) with Ms. Sally Smith-Clemens, Product Manager of Olympus Imaging America, Mr. Richard Pelkowski, Product Manager Digital SLR of Olympus Imaging America, and Mr. Toshiyuki Terada, Product Planning Manager Olympus Tokyo just prior to the release of E3.
http://fourthirdsphoto.com/special/E3interview.php
Tony asked about the 'refit' of lenses to SWD
Terada said that “We have to consider which lenses, in priority, we will change over. As well as, we are going to look at the development of some single focal length [prime lenses]” Mr Terada said. No matter what, it looks like we should see more prime lenses to be released in the near future.
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I am also aware that Olympus's strategy was to fill out the range with 3 levels of zooms first, and then to look at primes. And elsewhere again, in a translation from a Japanese interview they spoke of something called 'thin glass', which I take to mean pancake prime.
For Tony himself, who is not to know all that is happening with Olympus he says "I believe that we will see primes in the market this year, or at least announced, but till this point it would not make since. Add another long macro, maybe another super telephoto, and then produce a 1/2 dozen prime lenses."