I just went through the same thing with my trailer. The guys at Lordco & NAPA both looked through their catalogues & couldn't find a sleeve to fit my spindles. SKF had the best selection, but none were what I needed.
I ended up cutting the old spindles off & having a local welder install new ones I was able to find locally.
The cool thing about the new axles was that they came with a stainless steel sleeve already installed. And only cost $65.00 each.
It's a good thing I did change them out, because when I was cutting the old spindles off, I noticed there was a fair bit of wear where the inner bearing sat. Was hard to see until I had the axle on my bench.
Total cost with $150.00 going to the welder was under $300.00. A new axle was quoted at over $800.00.
I had to cut off the U bolts, so new ones added some to that total. Plus new bearings & seals, of course.