I know this is an old thread, but if the audience is still hanging around, here is my implementation involving my Kreitler 4.5 rollers and Killer Headwind. I use a wooden chasis and use a wooden block to keep the Killer Headwind up in the air a couple of inches to clear the base and operate in concert with the rollers. Still, even though I have ridden fixed rollers for years, I cannot get myself to stand out of the saddle. I just don't know if I have the bungee tension quite right.