I thought I'd give my latest acquisition, the Canon 50D, a try out at a higher iso. These 2 shots were taken at 1600 iso, the lens was a Sigma 18-200mm F3.5-6.3 DC OS.
Although not brilliant, still usable I think.
Both pics have had minimal processing, mainly some slight High Pass filter sharpening after re-sizing for the web.

f4.5 @ 1/25 sec

f4.5 @ 1/80 sec
Mike