Years ago I had a Nikon D70 converted to be sensitive to Infra Red light. I bought a conversion kit from Lifepixel and had Myles Whitehead, who is the camera technician who looks after my cameras, do the conversion.
The camera has not had the focus system adjusted to correct the point of focus for IR light, but with careful technique that is not a problem.
The results are very different to a colour camera and I go through spells of using the camera mixed in with long gaps when it sits in my camera case.
Over the last week I got the camera out and started to enjoy using it again.