It's all happening. MashupCamp is a loosely joined open space event for mashing APIs and open source. Socialtext set up a Kwiki for the event, which will be at least one day between February 18th-25th around Palo Alto. Co-organizers David Berlind and Doug Gold are nailing down the location, but signups for a maximum of 250 developers and observers are open.
Using my supreme design skills, I whipped up a logo:
Which sucked, so Pete Kaminski made one:
Which is a trip. And Chris Radcliffe made one too:
Now the logos are in rotation on the wiki. You too can contribute one (expect modest fame, possibly T-shirts, no fortune), and people are voting on this wiki page.