Have you considered custom made leaf springs? Custom can also be made for stock height ( no lift). I use Alcan on my Jeep. They would need to know eye to eye length. Vehicle weight on front and rear axle. Is the axle center pin 'centered ' on the leaf spring? Offset by how much? No clue on shipping. There are other custom manufacturers too. They have specific requirements for ubolts. Have to ask them or your preferred vendor.
sources many of their parts from Thailand and surrounding areas. I haven't used them much, but the parts would be used OEM and shipping to you might be much less expensive.