Heh... I think it would be better to break the arguments into possibilities.
Lightsaber- A hilt, which can be triggered to get the extremely hot and glowing tube out of it. Pissiblities?
The first instinct would be to think it's energy (lazer technologies) wrong: the lazer is a ray of energy in the form of volumetric light and heat, as we all know, the rays may not have an end in any case (unless the emmiter is off, and then it becomes a line travelling infinitely in the direction of emmiting, which still means no end to advancement of it.) If it is energy in any form, than there would have to be a perfect reflector on the top. This would bring the necessity of the central pole in the blade, which holds the reflecting disk (or whatever the form you imagine it,) and of course not only it would be hard to really stop it (although it would solve the question of power use, just one shot is enough o keep it up forever,) but any tiniest fluctuation of the reflectors (One must also then be included at bottom) would result in colossal outcomes. Thus pure energy blade for the lightsaber if made, still requires something solid in it, and will involve risks beyond measure, which makes it obsolete.
The next thing I though of would be another combination of light and heat - Plasma. Plasma, unlike energy, is a state of substance, furthermore, it has side effects of extreme heat and light emmission. Also, unlike energy, plasma is substantial, thus is dependant on gravity. All we need is the plasma to take the form of a cylinder, which may be achieved by extreme magtnetic fields... This would still require something solid in the blade, but would take care of endlessness in the previous part, and allow flexibility to the blade (as it would stick to it.) Though it would be really expencive (expensive?) to create a rod which can resist temperatures so high. Thus, it might be possible, though expensive (expencive?) to create the "lightsaber" AND "lightwhip" but it would still leave the problem with turning it off and add the problem of great energy consumption...
Conclusion: No "energy" weapons are possible, but plasma based recreations of idea of "lightsaber" and "lightwhip" ideas would be realistic... in... 20,000 years. =/
The question is would you use either of them. And would they be able to "reflect" the ranged attacks. Also this concept adds another point - in a "saber lock" the sword which has more gravity force drains the other lightsaber, which would make it rational to use a "blaster" in conjunction to lightsaber.
P.S. This also solves the problem with physics, for the blade would have the weight of it's mass (the saber is completely substantial) enhanced with the gravity between the saber and the land (and both are emmiters, and the smaller has to have bigger value of gravity force, which would make it really hard to wield, thus a jedi would have to have an extraordinary physical development.)
But it's just fiction, so I will go and enjoy it without all that crap. It's just the moment when Luke arrives at Dagobah to meet Yoda, I like the scene so much... And I wouldn't use a lightwhip...