We run oil samples for every fleet vehicle we service. Generally I find the conventional oils start breaking down around 3,500 - 4,000 miles. The good quality synthetics like the Rotella, show minimal breakdown at the 8,000 miles we service them at. I can venture to believe that 10,000 is not a stretch.
I agree though on a motorcycle you don't want your oil breaking down and at high RPM's not circulating well.
@mabupa and
@Yellow09 are prob on the mark with their 5-6,500k service interval on the Busa. For me, the seasons are so short here in NY I rarely break 3-4k in a season. So I pretty much change my oil at the start of every season....But I do keep an eye and if I do get close to exceeding 4k I go ahead and change it. It just sucks when I do because It is like throwing away oil, as I still change it at the start of a new season. It is like my pre season ritual LOL.