Can a CRJ700 full of passengers fly from LA to Japan with no layovers if the entire cargo deck is converted into a large fuel tank?

I can speak confidently but not authoritatively on this, so let's consider this answer tentative. I would be glad to be corrected.

Military gliders were replaced by helicopters after World War II, and no one seems to have found a civilian use for large ones. Unpowered flight is a sport, now, so there don't seem to be any with more than 2 seats. The only recent exception I can think of is the Space Shuttle, which was unpowered during its return from orbit.

Birds can't read the FAA regs.

Not true. High marks will give you your choice of what you want to fly. So if you want to fly the F-22 make sure you get to the top 1% of your class. Same goes if you want to fly say the KC-135.

money its all about the money why discount when you can charge full price.

You can use a program like flightaware.com to see flights that are on an instrument flight plan. That won't get you any info on most flights though.

Yep.

As the wings are lifted by differences in air pressure and gravity acts on the fuselage, the extra fuel load in the wings won't really affect the curvature. Rather, this is for the large storage capacity (volume) of the wings, and the safer option that your fuel tanks are outboard, rather than crew / passengers sitting directly on top of a "belly" tank. In event of a fuel-fire or crash, there is still a chance of fire being extinguished, or fuel-laden wings breaking away in a major crash. The spread-out mass of the wings also adds to stability by increasing the inertia.