Denti said: "There is an option (according to Chris Brady) of AoA indication for the 737 which even has a nice green band for approach AoA values. I do not know if there is any airline out there using it or if it is rather used by military applications. "
That's not an option that's an FAA requirement and known as the Low Speed Cue. It is the electronic equivalent of a painted green line on a simple IAS. It's usually set at 1.3 Vs and is a second order approximation driven from normalized AoA. It gives a reasonable result at low altitudes but it has been known to show up in cruise when it definitely does not match anything - one of our Authority TPs once characterized it as "an abomination unto good airmanship" (guess who's 525 regs DON'T require the green line).