My Shadow had 50,008 miles on it when I put it away for the winter. I can only assume it hasn't changed since then.
I have run across many liquid-cooled bikes with well over 50,000 miles on them, many with over 100,000.
The most I ever saw on an air-cooled bike personally, is a bit over 41,000.
However, there are some air-cooled bike that are known for being high-milage bikes. The Yamaha Virago 750 will do well over 100,000 if properly maintained. The newer fuel-injected Harleys are breaking 50,000 without rebuilds, but I can't say how much more than that for any experience.
What it comes down to is maintenance. You could have 10,000,000 on a Model T if you didn't mind dumping the money into it to keep it on the road.
--Justin