Midnight might not be the best time to mess with math...but this looks good to me...I might be fixated on something that is not correct and can't see it...seems simple enough to me...any thoughts?
~R~
edit 20120819: I may have found my mistake...
E x B = - (v x B) x B = B x (v x B) = vB^2 - B(v.B) -> v = (E x B) / B^2, where v.B = 0 because they are ON. Here v.B = v dot B.
So I am OK w that.
Now have I made the same mistake w calculating E from v?
It looks to me like (where I use B^2 == B2)
vB2 = E x B -> vB2 x B = (E x B) x B = B(E.B) - EB2, and that cancels B2 on both sides, and means that I must negate the RHS to get E = -v x B. again.
~R~