Actually,
www.allelectronics.com has an AZ971, available for $1.25 ea., in qty 10. The site says the contacts are rated for 30 amps, but the manufacturer says it's rated for 40:
http://www.azettler.com/pdfs/az970.pdf
(PDF, 2 pages)
The problem is that they don't give out any contact resistance, except for a "less than 100 milliOhm, initially", under what they call a "24V, 1A voltage drop method".
The "PWR_GOOD" line isn't always on: it only turns on when all output voltages are OK. What I'm not so sure about, is the power off sequence.