I think switched outlets are more common on dedicated amps than receivers these days. If you want a cheaper alternative, this
Smart Strip senses when the device plugged into the primary jack is drawing power and will automatically switch on the auxiliary outlets. When the device plugged into the primary jack is in standby / low power, the other jacks are turned off.
Edit: Ah, ReUpRo beat me to it. Might as well add this:
If the receiver and the Panamax are in different parts of the room, you could use the 12v trigger out of a receiver to trigger
this Powerflash interface to turn on this
appliance module remotely. Not sure what shipping is, but that's probably still cheaper than the Niles relay-controlled power strip. Although it's lower cost, it adds a layer of complexity.
I'm using the Niles on my bass shaker amp and it works swell. If I ever get a sub with a defeatable auto-standby, I'll probably use it for that as well. I guess it just depends on whether you're more motivated by elegance and heavy duty reliability or a bargain.
I'm interested in the answer to crossedover's question as well. What model Panamax? Some of them already have a 3.5mm 12v trigger input. If yours does, then no triggered power strip, smart strip or other sort of additional relay outlet is needed. You might already have what you need.