You might have the Hayes 2500# axle, looking up that is how I found what mine was. Mine actually still has an aluminum tag wrapped around the axle that says Hayes, 3000# capacity. So maybe it's a Hayes 3000# axle, but regardless it has Hayes 10 x 1 5/8 brakes and the funky bearing setup.
I found the Hayes brake shoes discontinued back when I started my conversion back in late 2002. So finding them would probably be a miracle by now.
Here's a recent thread where someone was wanting to redo the brakes. They decided to re-line the shoes, which is probably the most cost effective thing to do. Another option would be to just replace the axle with a 3500# axle and have common brake parts.
But for me I like a challenge and to do something different. So here's the link to the thread where I described my disc brake conversion.
If you do have the Hayes 2500# axle, judging by the rest of your work, I bet you could pull off the disc brake conversion if you wanted. Only expensive thing would be an electrohydraulic actuator. You could just weld on new backing plates and do less work than I did. I couldn't weld at the time but had plenty of machining experience and machines were available.
Hopefully I still have the part numbers and all. I saved all my receipts, old parts, and design info and put it in a box on the porch, including the .540 reamer I bought from McMaster for the wheel studs.
The bearings, races, and seals for the Hayes axle are standard items, but they were in a combination that they don't use anymore. Like the outer bearing from one size axle, the inner bearing from another, and the seal from another. I told Champion Trailers what I needed and they put together a custom package for me for the same price as standard.