At several points I have held the world record for beggar-my-neighbour game length. Richard P Mann maintains the de facto official registry of record-length games.
Here is the longest game I have found (8344 turns, 1164 tricks):
player 1: ---AJ--Q---------QAKQJJ-QK
player 2: -----A----KJ-K--------A---
Here is my previous record (7972 turns, 1106 tricks):
player 1: ----K---A--Q-A--JJA------J
player 2: -----KK---------A-JK-Q-Q-Q