Installing On Board Air

I did a search on this subject but got very little help. I'm going to install on-board air but I'm not sure where to locate the compressor. Has anyone done this before, if so where under the truck did you put the compressor? Did you install an air tank as well? How many gallons? I've got everything I need off my pickup truck except the air tank (5 gallon) might be too big to fit under an H3 so I'll be needing a new one of those. Otherwise I'm good to go once I decide the best location for the compressor. Any suggestions?

This looks like a good idea.
 
 
http://www.off-roadweb.com/features/0606or_2006_amstar_hummer_h3/photo_16.html
 
 

WOW!  That is the best setup I've seen!!