So, on a leaf spring where the pin is off set to one end, like the F150 springs in the rear of my Toyota, are there any advantages or ill effects of running the short side back vs the short side forward? It would seem that I could gain some wheel base if I wanted if/when I go to bigger tires.

I dont have an answer, but I did install my rears that way. I havent finished the scout yet so I dont know how it will work . I do know it will need a traction bar to prevent axle wrap.
I have subscribed to this thread and will watch for some input.

Running the short side back will not do you any favors unless your only goal is to increase the wheelbase without actually moving the mounts.

The section of the spring on the side of the axle opposite of the shackle (front half of the spring in this case) does surprisingly little flexing. Sure, it flattens out a little, but if you watch the spring cycle you will see that the shackle end flexes much more, especially since it is longer.

So...putting the short side back just lost us a lot of flex. That's not it, though. That long, flat section that did really well for flex before? Yep...it still does good for flex in the way of spring wrap so you get a bunch of hop and broken u-joints.

Don't get me wrong...plenty of people have run them backwards like that. It all really comes down to the specific vehicle and what you're expecting to get out of it. As a general rule of practice it is not advisable though.

I have been debating replacing the rear 56" springs with 63". that would fix the wrap problem (even though I would still have a traction bar) and I would gain a bit of flex.

This can be done succesfully but is usally not recommended and makes for short life span leafs.

The best way to do it, is to basterdize the pack. By this i mean flip just the top leaf around and leaf the rest of them in there orginal location. This will give wheelbase length and flex should be about the same. However you must keep good shackle angles as well. And that may mean relocating the mount. Its do-able, but if you ask me not worth it.