And the buyer(s) would know it's an authentic "ticket" because they can see it's been issued/verified by the concert organisers?
Yes.
And could I specify that a "ticket" cannot be resold? So the first buyer has to redeem the ticket at the door to stop dealers reselling for huge amounts?
Well, it is possible to detect whether ticket was transferred to another address before it was redeemed. So organizers can ban tickets which were transferred, which would make reselling meaningless.
Dealer might resort to a trick: instead of transferring ticket to a new address, he will sell private key of his own address. However if buyer receives a private address he cannot know whether he bought an unique ticket or same ticket was sold to other people many times. So buyer will buy from a dealer only if he trusts this dealer.
So this discourages reselling, but does not completely eliminate it.