Its alot more common than you think. Search "one link suspension". Back in the day I believe someone even competed in top truck challenge with the trailer ball suspension.
Most of the time the joints used are motor grader pivot joints or joints made specifically for a one link.
SU Joint for one link suspension by FrogFab - Pirate4x4.Com : 4x4 and Off-Road Forum
Ive even seen large heims used for this.
