Just got the latest Servo in the mail, and the back page is an ad for a new sonar unit from Parallax, called Ping))) (Yes, the ')' is part of the name)
It looks to be comparable to the SRF-04. It's a three pin unit, power, ground, and a single ping for activate and return.
Also, it is $25 each, or 5 for $100.
The data sheet on the parallax web site gives timing diagrams, but not a beam pattern.