I'm not currently a Gretsch owner (though hope to be one at some stage). I've been casually on the lookout for a 5120 (Electromatic) or 6120 (Pro-line) on adverts.ie for a while now. One thing I'd say about buying second-hand is they don't seem to turn up very often. And when they do, often it's not exactly what you want, so buying second-hand, from Ireland at least, may not be that practical.
One thing you could do as a middle-ground, is get an Electromatic and upgrade the pickups. TV Jones classics are generally thought to be an improvement over the stock pickups. From what I've read, the stock pickups on the Electromatics are more Gibson/darker sounding, and pickups like TV Jones classics give it more of the Gretsch sound (while stock pickups on the pro-line are generally thought to be fine).
I'd also recommend having a look on the gretsch-talk forums, very helpful guys on there. They have an archive search so you can see if similar questions to your own have been asked before.