Actually I *would* like to see a beam sabre. At least one more use -- I can either slice you, run you through, or slap you silly with it. A beam saber's can only do 2 of the 3.
Hard to say about the origin of the lightsaber. It's probably a case of borrowing from each other... Lucas probably saw some poster or show with a energy weapon and refined it to the lightsaber, while Tomino probably saw Star Wars and refined his weapon into the beam saber.
I fI recall, Tomino was inspired by Star Wars to the point where he wanted to do the Gundam in pure white so it would look like a stormtrooper.
Mmmh... If memory serves, I believe Tomino wanted to make the RX-78 looks like the White Knight, the hero from the old traditional legends: I do not think the Stormtrooper design has a real link with this, all the more as imperial soldiers are supposed to be 'evil' and the Gundam on the 'good' side of the One-Year-War...
Yeah, but the Empire had WAY cooler uniforms.
Vader could whip Ackbar any day.