You really shouldn't ask about how long! I originally ordered the trike kit thru Trike Traders here in Florida from Hannigan for my Kawasaki Nomad back in February. Then the factory burned down where they stored their molds. After stringing me along for six months, they finally admitted they weren't going to re-do the Nomad mold.
They were the only company offering a trike kit for that model. I traded the Nomad in on a Road King and re-ordered a trike kit, still with Hannigan.
It's been a ten month process.
It IS independent rear suspension. No engine upgrades yet.