I was checking to see if anyone had used the minivan axle and came across this thread.
I've actually used one on my utility trailer and it has worked very well. I found the mounting was easy because I didn't have to buy U bolts. The axle has a flat (might need a small piece of stock to bridge a gap) with four bolt holes. Having had 2 minivans, I have plenty of rims and tires as well as the assurance that the tow vehicle spare can be used on the trailer and vice versa.
My next challenge is building a ttt with the minivan axle as my base.