The need for speed: Four crazy 90mm f/1.0 Lenses

Most über-fast lenses (with f/1.1 or faster aperture) do have a focal length between 25-50mm. But there are some (crazy) exceptions. Take a look at the follwoing four items (clicking on the link will show you the lens on eBay):

1) FJW Industries Lens 90mm f/1.0FJW Industries Lens 90mm f/1.0FJW Industries Lens 90mm f/1.0FJW Industries Lens 90mm f/1.0FJW Industries Lens 90mm f/1.0FJW Industries Lens 90mm f/1.0FJW Industries Lens 90mm f/1.0FJW Industries Lens 90mm f/1.0FJW Industries Lens 90mm f/1.0FJW Industries Lens 90mm f/1.0FJW Industries Lens 90mm f/1.0

2) Leica Leitz 90mm f/1.0Leica Leitz 90mm f/1.0Leica Leitz 90mm f/1.0Leica Leitz 90mm f/1.0Leica Leitz 90mm f/1.0Leica Leitz 90mm f/1.0Leica Leitz 90mm f/1.0Leica Leitz 90mm f/1.0Leica Leitz 90mm f/1.0Leica Leitz 90mm f/1.0Leica Leitz 90mm f/1.0

3) Varo Optical Inc. High Speed Lens 90 mm f:1.0Varo Optical Inc. High Speed Lens 90 mm f:1.0Varo Optical Inc. High Speed Lens 90 mm f:1.0Varo Optical Inc. High Speed Lens 90 mm f:1.0Varo Optical Inc. High Speed Lens 90 mm f:1.0Varo Optical Inc. High Speed Lens 90 mm f:1.0Varo Optical Inc. High Speed Lens 90 mm f:1.0Varo Optical Inc. High Speed Lens 90 mm f:1.0Varo Optical Inc. High Speed Lens 90 mm f:1.0Varo Optical Inc. High Speed Lens 90 mm f:1.0Varo Optical Inc. High Speed Lens 90 mm f:1.0

4) Canon XI 90mm f/1.0Canon XI 90mm f/1.0Canon XI 90mm f/1.0Canon XI 90mm f/1.0Canon XI 90mm f/1.0Canon XI 90mm f/1.0Canon XI 90mm f/1.0Canon XI 90mm f/1.0Canon XI 90mm f/1.0Canon XI 90mm f/1.0Canon XI 90mm f/1.0 -> Images samples on flickr

I found image samples for the Canon lens only and I don’t know if you can use all of them on a MicroFourThirds camera. Let us know if you ever used one of those lenses on your camera!
Thanks!