The 2007 Masters World Track champs are being held in Sydney right now, and I have to say (as a master myself) that's damned quick...1 David Le Grys (GBr) 0.34.14 (52.73 km/h)
I've done just one timed 500m run on Sydney's Tempe velodrome, a 40.09sec effort. I reckon I could get below 40 with some practice... but under 35secs?? Yikes!