don't know what you guys got against the tanks in the cab - like Jim Carter points out in his tech articles, if your truck got hit hard enuff to burst the tank behind or under the seat inside a double wall cab, you'd be instant meat paste anyway, whereas gettin rear ended by some SUV would much more likely rupture that neat little amateur-installed plastic tank just 1 foot ahead of the back bumper, not to mention the greatly shortened life span of a tank exposed to the road spray and debris
my tanks stay where GM put'em, just gotta maintain things to prevent leaks and fumes - yes 49dream, you can easily pull the tank and fix the leak, or have a rad shop do it for ya, and it'll cost a fraction of installing a new tank in a new location
Bill