Now there is good news on the D7000!
I got the info today that Optic MAKARIO in Germany found a way to modify a Nikon D7000 in such a way, that the spoiling of the image through that built in shutter control IR LED system at high ISO / long exposure times will be suppressed. ISO 800 and 1600 are now possible to use with very good results. The effect still exists but in much lower amounts, so at very long exposure times and very high ISO settings it will still be visible though.
This was tested out good, I was told, for shooting IR and my personal assumption would be, that this can be applied for UV work, too.
Stay tuned, more will follow on that fascinating subject...
P.S.: (as of July 2011) lifepixel.com now offers conversions for D7000 in the US which also overcomes that problem and allows high ISO and long exposure times without fogged images!
More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos