The picture you show is a Schwinn Paramount branded part, though the handle bar clamp seems like something else. They turn up occassionally, I got one on ebay a few years ago for a Paramount track I'm still trying to find the original parts for.

The Ambrosios turn up on ebay regularly, I've gotten a couple, as do the all steel Major Taylors but they bring at least 100., usually more to win.

I don't know anything about the Titans...