OUCH !!
I agree -- Volvo is not only expensive -- their return/restocking fee -- Well .. I won't go there -- It's to painful !!
Here are some Big Truck Salvage sites that I've gotten from the Truck Paper:
http://www.americantruck.com
http://www.rockymountaintruckparts.com
http://www.samsriverside.com
Hope the above is of some help -- You may also want to go to/call a Truck Stop/Shop in your area -- and pose this question also.
Side note -- I to am now interested in XM Radio -- After seeing in a magazine -- Delphi's versitle/movable receiver !!
Tootles ......
OLDphoneman