Kingpin change
I went the opposite way. In order to clear my toolbox from the front corner of my trailer, I went from a straight down kingpin to one that extends 9" forward. Although the brand on mine is Leland, when I called them, they advised that you can only get them through the dealer that handles your brand of trailer (Jayco in my case) due to liabilities. Leland made one that reaches something like 22" forward, but in the case of my trailer, they wouldn't authorize it due to weight and torque considerations.
I guess the upshot of this is that I suggest you contact Nash and ask them. I realize going to a straight down one should have less torque and such.
My swap was about $150...