KiNgBrAdLeY7: So, any estimations?
I don't know, but I would like The Grand Gwent Tournament, hosted at Oxenfurt, where you'll have to beat 10+ good players. It could have a ladder, just like a real tournament. If you loose before finals, you are out. The price? Why not one of the regular cards, but with gold ornaments, that would replace the one you already have (if you have it). Entry fee: 1000 crowns. It would also be a great way to win cards that don't have a fail-safe (Vegelbud Residence quest). It's like additional 20h of gameplay :)
It shouldn't even be too difficult to implement. No new dialogue lines needed, just new cards.