The 2011 PMA Australia Expo will take place on June 24-26, 2011 in Sydney. Pentax is rumored to announce their mirrorless interchangeable lens camera on June 23rd. You can expect the first reports on the new camera from the show's floor on June 24.
The last PEN News Weekly newsletter also confirmed that Pentax will be coming with a new mirrorless camera this summer with a 70,000-80,000¥ price tag for the lens kit. Expect the US price to be lower.
Olympus decided to have their announcement after the expo, on June 30th.