WOD is selling them. If you want to piece meal it. Durasolid spindles are cheap. There was also someone I think on the FB hardline selling DRW hubs machined for SRW.
Just ordered a set of D60 Super Joints from him last night. We BS'd about Dana 60 load bolts and such. Nice guy. Was surprised to get a response on a Sunday evening.
I got lucky a couple of months ago and found a NOS TJ one on Ebay. You will need 3 TJ ones to make them correct length. There is a YJUnlimited Facebook page and also a TJ6 page on facebook. You may have luck there.