YouTube executives and spinmeisters have been pushing back more aggressively at the perception that the video site is a great big drain on Google’s bottomline, probably  losing $200 million to $500 million a year by some estimates. These execs say that hundreds of major advertisers are taking spots on YouTube against “hundreds of millions” of video views every week.

The problem with this is the lack of precise details. How much revenue is YouTube generating from these monetized videos exactly (even approximately)? And how much does it cost to stream and store those hundreds of millions of videos every week? Google and YouTube decline to provide any numbers other than to say things are moving in the right direction. Wall Street and investors are yet to be convinced.

Goldman Sachs analyst James Mitchell is the latest to have a shot at a respectable estimate for YouTube. He says it will generate around $300 million in 2009. He also thinks the best is yet to come from YouTube — and that Google will see some benefit.

We believe YouTube revenue will grow at 40 percent year-over-year or faster in 2010 as YouTube is generally under-monetizing its home page traffic versus peers, and as its home page is a natural venue for studios to advertise new movies.

For Google investors, the most important part of Mitchell’s analysis is that he thinks display advertising, of which YouTube is a major part alongside DoubleClick, could add 1-2 percent to Google’s revenue growth.