eBay and Craigslist finds

The BB-30 "adaptor" is included on some bikes due to the expense of the cranks compatible with the bb-30 (I think the SL Alumn. are around $750..) so it is cheaper for the companies to include more mainstream cranks... Now as to your question. There is a sleeve in the bottom bracket right now that is allowing your threaded BB to fit. That can be pressed out with the correct tools (any Cannondale dealer should have these) and this would allow you to fit your BB30 Style cranks in.

Not sure if these posts help but this comment suggests you can use a standard bb ...at a cost

Yes, but you cannot fit a BB30 to a standard bottom bracket shell, which is what I was after.