I'm building a 12v based boombox (500 watts+ under 60lbs) and I'm trying to find the best benchmark for power, volume, weight and decent sound quality. The best I can find so far is Fender

Fender:
http://www.fender.com/products...hp?partno=0691007000
-50 lbs
-500 Watts

I know that the Telefunken 1M is one of the loudest traditional boombox. Are there any other "portable" soundsystems in this range I should be aware of?

thank you!

JVC Kaboom, for sure.
Google it, & you'll see

Here is mine homemade Blaupunkt MasterBlaster...

http://www.youtube.com/watch?v=E_0IaCmsie4