Greetings!
I have been reading and re-reading the talents as well as the two-weapon fighting rules in the BC book. And, from what it seems you can hit an insane amount of times. The two-weapon wielder talent specifically states that you can do a Standard attack, Swift attack or Lightning attack with both weapons. So far so good, 2 Lightning attacks per round, that works.
Now, if you look at the Furious assault talent, where you can use your reaction to make an additional attack, things get interesting. As far as I can tell, you can do a Lightning attack with that additional attack, and combine this with Two-weapon wielder. The only "combat talent" I have found, wich specificaly states that it can not be combined with Swift attack, Lightning attack or Two-weapon wielder, is Counter Attack.
Now, hopefully I have missed something, since I think that 4 lightning attacks per round, admittedly with no chance to dodge/parry, will be extremely devestating.