I had my Nikon D70S modified by LifePixel. I had been shooting a Sony 717, with an R72, and a ND8 filter for IR. It had me hooked so when the right time came I bought the D70S and sent it immediately to LifePixel for the modding.
I am not sure who's doing Mods across the "Pond" I know there are several folks in Austraila that do it, you might look around or give shooting with a screw on R72 or similar IR filter to see if you like the results. The only thing with shooting with a screw on filter is the increased Shutter time, but sometimes it actually enhances the images.