Assuming the reports that the video/sound editing portions of SF are for sale (and even being negotiated now), one has to assume that the upgrade to Vegas is an instant sale to a known number of liscensed holders. Because of that, Vegas becomes an important negotiating tool for SF.
IMHO, there will be no release until a buyer is finalized and said buyer determines how they want to handle the upgrade.
Because of this uncertainty, it could be a while (6 months or more??) before we have an upgrade in our hands. The teasers we are seeing here send a message that Vegas 4 indeed exists and we should hold on . . . Take this with a grain salt as I'm old enough to have been wrong many times in life ;)
Of course, the other possibility is that releasing a good product at a price loyal users would feel compelled to pay to upgrade is a way to bring cash into the organization, which seems to be the foundation of Sonic Foundry's current situaiton.
There is a training seminar being given (hosted by the COW forum) running Feb 18-20. I believe they are giving away a few copies of V4 - so theoretically it should be released by then...
I just tried calling their 800 customer service. Asked them about the release dates for both Vegas 4.0 and DVD Architect. The gentleman was very kind in answering my questions. . . basically. . .
"No, we're unable to tell the release dates of these products until the official notice is posted. Just keeping checking the web site."
. . . and. . .
"Yes. Those web shots of the products are authentic."