Vash went to the boot guy because like his gun, his boots require a very skilled person to work on them. As for what's in the bag, please for the love of god start reading the actual mangas of series instead of just watching the anime... The guy's head is in the bag, check out these images from the manga...


http://i96.photobucket.com/albums/l177/TheCreek_2006/trigun/trigun004.jpg
http://i96.photobucket.com/albums/l177/TheCreek_2006/trigun/trigun005.jpg
http://i96.photobucket.com/albums/l177/TheCreek_2006/trigun/trigun006.jpg
http://i96.photobucket.com/albums/l177/TheCreek_2006/trigun/trigun010.jpg



hopefully that will clear some things up for everyone here..