Vinny, I have e-rail in my trailer and I fabricated a mount to hold them. I started with an e-rail clip, which looks like this:
I then cut a piece of pipe that is very close in diameter to my wheel axles. I had to cut out a small section at the end of the pipe so it would slide over the e-rail clip and then welded the two together. In the picture above, using the orientation that it is currently, the pipe would slide over the top and go vertical from there.
The pipe is just long enough to extend past the wheel so I can put an r-clip through a hole I drilled. Now, I have e-rail throughout the trailer and I can mount the wheel wherever I choose. I even mounted a couple small pieces in my garage so I can hang them in there over the winter. Pretty simple and really cheap.